The Latest on the fire that swept through Paris' Notre Dame cathedral (all times local):
Among those watching with horror as fire engulfed the iconic Notre Dame Cathedral was a U.S. Supreme Court justice.
Justice Stephen Breyer is an architecture lover who heads the jury of the annual Pritzker Prize, the top international prize in architecture.
Breyer watched TV coverage of the Paris blaze in his chambers and says it was "horrific" to see the legendary building in flames.
He said Tuesday there was a moment where it seemed "awful and irredeemable." But he said his spirits rose as he realized the cathedral could, and would, be rebuilt.
In his words, "The future is still there. It's not going to be a void at the center of Paris."
Breyer says his feelings for Notre Dame stem from his very first trip outside the United States when he was 18 and an exchange student in Paris.
Hundreds of people have gathered near Notre Dame Cathedral in Paris for another prayer vigil.
A crowd carrying candles and singing religious songs marched from the Church of Saint-Sulpice and grew on the way to a Left Bank plaza that faces Notre Dame.
The Saint-Suplice church, built in the 17th century and important to French Catholicism, caught on fire last month but had nowhere near as much damage as the older cathedral.
At the plaza by Notre Dame on Tuesday night, vigil participants sat around a statue of the Virgin Mary while listening to a small string orchestra and doing more singing.
Organizers said in a statement they want to show their attachment to Notre Dame.
The United Nations says it will be supporting the French government in rebuilding fire-ravaged Notre Dame Cathedral through its Paris-based cultural agency UNESCO "in whatever way they feel is most necessary."
U.N. spokesman Stephane Dujarric said Tuesday that the cathedral is a UNESCO world heritage site "so I know our colleagues there will do whatever they can" following Monday's fire.
He said Secretary-General Antonio Gutteres, who tweeted Monday that he was "horrified" at the blaze at the landmark cathedral, "will fully support UNESCO's efforts."
The Archbishop of Turin says that the Notre Dame fire brought back painful memories of the 1997 blaze that tore through the chapel built to house the Shroud of Turin.
Monsignor Cesara Nosiglia on Tuesday recalled the dramatic events of April 11, 1997, when firefighters rescued the shroud — venerated as the holy cloth in which Jesus was wrapped after his crucifixion — from its bulletproof, climate-controlled glass case. The shroud was not in the chapel itself, which was nearly destroyed, but in another area of the Duomo cathedral where it had been relocated years earlier during renovation work.
Nosiglia said "our suffering has been renewed, because Notre Dame, like the Duomo complex, doesn't just mean history, art and stone. These monuments are living treasures of the churches and of the people. They have universal value."
The dome of the Chapel of the Holy Shroud in Turin inside the Duomo will be illuminated in the colors of the French flag Tuesday night in an expression of solidarity with France. Restoration on the chapel was completed only last September, after being closed for 28 years. The cause of the blaze was never determined.
Pope Francis has phoned French President Emmanuel Macron to express his solidarity over the fire at Notre Dame, hours after the Vatican culture minister offered art experts who could possibly advise on reconstruction efforts.
Vatican spokesman Alessandro Gisotti said Francis called Macron Tuesday and tweeted: "During the exchange the Holy Father expressed his solidarity with the French people after the blaze that ravaged the Notre Dame cathedral in Paris."
Earlier Tuesday, Culture Minister Cardinal Gianfranco Ravasi suggested that experts from the Vatican Museum could offer their services as the French begin to rebuild. He stressed though that Notre Dame is owned by the French government and has autonomous sources of funding.
Francis sent an official message of condolences to Paris Archbishop Michel Aupetit, in which he called Notre Dame the "architectural gem of a collective memory."
French President Emmanuel Macron says he wants to see the fire-ravaged Notre Dame cathedral to be rebuilt within five years.
Macron said Tuesday in a televised address to the nation that "we will rebuild Notre Dame cathedral even more beautiful."
He added that "we can do it and once again, we will mobilize" to do so.
Macron, who also said "we have so much to rebuild," thanked firefighters and police and donors who are giving money for the renovation.
The president of the University of Notre Dame said the school will donate $100,000 toward the renovation of Notre Dame cathedral following a devastating fire.
The Rev. John Jenkins announced the donation Tuesday, a day after the fire destroyed the cathedral's spire and roof.
Jenkins says the bells of the Basilica of the Sacred Heart on the university's campus in Indiana will toll 50 times Tuesday evening, to represent the 50 Hail Marys of the rosary and mark the start of the Paris cathedral's rebuilding.
Jenkins says the cathedral's "exquisite Gothic architecture has for centuries raised hearts and minds to God. We join in prayer with the faithful of the cathedral and all of France as they begin the work of rebuilding."
New York Governor Andrew M. Cuomo has directed that One World Trade Center's spire be lighted in the colors of the French flag in solidarity with the people of France and the Catholic community worldwide.
Cuomo says the lighting on Tuesday night will be a tribute to the fire-ravaged Notre Dame cathedral, "one of the world's most sacred and celebrated religious monuments."
The flags of France and the United States contain the same colors, but different patterns.
The French flag has a white center flanked with blue and red. The U.S. flag has red and white stripes, with white stars on a blue background in the upper left corner.
The White House says the bells of Notre Dame cathedral "will sound again."
Press secretary Sarah Sanders says President Donald Trump offered his condolences Tuesday to French President Emmanuel Macron over the fire that caused major damage to the iconic building. She says America stands with the French, the city of Paris and millions of visitors from around the world who seeks solace at the cathedral.
Sanders adds that France is America's oldest ally and that Americans remember "with grateful hearts" the tolling of Notre Dame's bells the day after the Sept. 11, 2001, attacks on the U.S.
She says "those bells will sound again" and closes her statement with "Vive la France!"
The extent of any damage to the bells and their support structure is unclear.
Spain's Culture Ministry says it has convened an extraordinary meeting of the country's Council of Historic Patrimony to discuss fire safety and other measures after a blaze ravaged Notre Dame Cathedral in Paris.
Culture Minister Jose Guirao tells Radio Nacional de Espana on Tuesday that the fire was "an alarm call" that is prompting authorities to review safety procedures and security installations.
He said Spanish cathedrals are well-protected "but there's no such thing as 100% safe."
The Culture Ministry says in a statement that the Council of Historic Patrimony was due to review safety procedures at a meeting earlier this month but ran out of time. A new meeting focusing solely on fire safety and other protection measures will be held in Madrid on April 26.
A Paris judicial official says investigators have questioned about 30 people after the fire at Notre Dame Cathedral.
He said most of them were employees working on the renovation of the monument.
The official, speaking anonymously on an ongoing investigation, said the cathedral's fire alarms sounded twice on Monday evening.
The first time, some people, including a fire official permanently working on the site, went to check under the roof and saw nothing. The second time it was already too late because the fire was too strong, the official said.
He added that 40 to 50 investigators are working on the case but are not allowed to enter the monument yet for safety reasons.
----By Nicolas Vaux-Montagny
Some will call it a miracle. According to Notre Dame's heritage director, only one piece of architecture inside the sacred building has been damaged.
Laurent Prades told The Associated Press that the high altar, which was installed in 1989, was hit and harmed by the cathedral's spire when it came crashing down in the flames. "We have been able to salvage all the rest," said Prades, who witnessed the recovery first hand overnight.
"All the 18th-century steles, the pietas, frescoes, chapels and the big organ are fine," he said. Among the most famous elements inside the cathedral, Prades added that the three large stained-glass rose windows have not been destroyed, though they may have been damaged by the heat and will be assessed by an expert.
Victor Hugo's novel "The Hunchback of Notre Dame" has rocketed to the top of the bestseller list of Amazon in France in its original version.
Meanwhile, the English translation of the 1831 novel is also number one in sales in the category of historical fiction.
Telling the story of Quasimodo, a deformed bell-ringer of the cathedral in the 15th century, the book helped rally support for Notre Dame's massive renovation later in the 19th century.
Campaigning for the preservation of the cathedral, Hugo described it as crumbling and marked by "countless defacements and mutilations," contributing to alert the public about the issue.
Video shot inside Notre Dame cathedral after the fire shows many tiles and columns have been spared by the disaster.
Images broadcast Tuesday by French news channel BFM TV also show several pieces of wooden furniture, including chairs and benches, seemingly intact, but there is a gaping hole in the nave's roof, with a pile of burnt debris lying underneath.
The fire which broke out Monday evening caused major damages to much of the almost 900-year-old building.
British Prime Minster Theresa May says the bells at London's landmark Westminster Abbey will be rung Tuesday afternoon to mark 24 hours since the fire broke out at Notre Dame cathedral.
She says this will be done "to underline our solidarity with France and her people."
Bells at cathedrals and churches will also be rung Thursday in a further demonstration of concern for France's loss.
The prime minister offered British help with the rebuilding of Notre Dame, calling it "one of the most beautiful buildings in the world."
She says the Westminster Abbey bells will sound at 5:43 local time (1643 GMT; 12:43 p.m. EST) Tuesday afternoon.
Serbia's president Aleksandar Vucic has offered sympathy and help to rebuild the Notre Dame cathedral after the devastating fire, but tabloids under his control called the disaster "God's punishment."
Many in Serbia are angry at France for reportedly displaying a flag of Kosovo outside Notre Dame for World War I centennial commemorations last year, and for taking part in the 1999 NATO bombing of Serbia.
Headlines late Monday on the websites of pro-government tabloids Alo and Informer said "God's Punishment has caught up with them." The articles were later removed after triggering outrage on social networks.
Some commentators said they are "indifferent" to the fire because of France's alleged lack of support for Serbia's claim on Kosovo.
Serbia does not recognize the 2008 declaration of independence of its former province.
Vucic said "all citizens of Serbia are sad over Notre Dame. We stand by our French friends and ready to help rebuild that symbol of French and world civilization."
Serbia and France have a long history of friendship. France played a major role in helping Serbs form their state in the Balkans after World War I.
French interior minister Christophe Castaner says there are still some risks that may endanger the structure of Notre Dame cathedral.
Castaner told reporters Tuesday after a brief visit to the cathedral that it is "under permanent surveillance because it can still budge."
He added that state employees will need to wait 48 hours before being able to safely enter the cathedral and take care of the art works that are still there. Some were too big to be transferred.
Castaner said: "We will be standing at (Notre Dame's) bedside."
All bridges surrounding Notre Dame cathedral in Paris are blocked by police — but that hasn't deterred tourists and Parisians from clustering as close as they can to the fire-scarred monument.
Sidewalks on the both sides of the Seine River were packed with curious spectators, both tourists and French bemoaning the disaster. Notre Dame sits on an island in the middle, the Ile de la Cite.
Still, the working river was in motion. A barge loaded with gravel slid past the cathedral Tuesday.
Annie Guy, a retired school principal from the Toulouse region, said she is "truly pained."
Guy said: "It's the beauty of a monument and our history." She recalled that French schoolchildren learn that the island housing Notre Dame was the birthplace of France.
Czech President Milos Zeman is offering France the expertise and assistance of leading Czech specialists to help restore Notre Dame cathedral.
In a letter to his French counterpart, Emmanuel Macron, Zeman said Tuesday that the Czech Republic is, like France, a country with many Gothic and medieval historic buildings and palaces. Zeman said that "the fire of Notre Dame affects us all."
Zeman offered teams of top restoration experts that work at Prague Castle, the historic seat of Czech presidency, which includes St. Vitus Cathedral, a Gothic architectural masterpiece.
Czech Prime Minister Andrej Babis said his country is also ready to send France financial assistance.
Greece's government has offered France assistance in restoring fire damage to Notre Dame cathedral.
The culture ministry says Greece is willing to provide academic experts and skilled technicians from its own restoration projects if help is needed.
The ministry has extensive experience with major conservation and restoration works on Greece's ancient and mediaeval monuments.
These include a decades-long program on the Acropolis of Athens, whose 2,500-year-old marble temples and other monumental buildings were badly damaged over the centuries by fire, explosions and warfare.
A ministry statement Tuesday expressed deep sorrow for the Notre Dame blaze.
German President Frank-Walter Steinmeier is urging his countrymen and others in Europe to contribute to the rebuilding of Notre Dame cathedral following a devastating fire.
Steinmeier said Tuesday that the footage of the landmark Paris building burning would "probably leave no one in Europe untouched."
He called for "the citizens of this country and the whole of Europe to support the reconstruction of Notre Dame."
Steinmeier added that the cathedral "is not only a great building, it is a great European landmark, a landmark of European culture and an important document of European history."
French companies Total and L'Oreal are pledging to each donate 100 million euros ($113 million) to support the reconstruction of Notre Dame cathedral.
A few hours after billionaire tycoons Bernard Arnault and Francois Pinault announced Tuesday that they would give a total of 300 million euros, oil and gas giant Total said it would contribute 100 million euros "to help the reconstruction of this architectural jewel."
Cosmetics maker L'Oreal promised the same amount to rebuild "a symbol of French heritage and of our common history."
Among other contributors, Bouygues construction group CEO Martin Bouygues said he and his brother Olivier would donate 10 million euros.
French President Emmanuel Macron will hold a Cabinet meeting Wednesday fully dedicated to the aftermath of the fire at Notre Dame cathedral.
The French presidency says a morning session will be followed by one in the afternoon focusing on the national fund-raising campaign and the reconstruction work.
Macron is to speak by phone with Pope Francis later Tuesday.
The French leader has postponed a speech and a news conference aimed at responding to the yellow vest crisis for an indefinite period, to respect "a moment of great national emotion." Macron was initially planning to announce measures this week addressing the concerns of anti-government protesters.
The French Bishops' Conference says that the bells of all cathedrals across the country will ring on Wednesday at 6:50 p.m. local time (1850 GMT; 12:50 p.m. EST), the time when the fire started Monday at Notre Dame in Paris.
The Bishops' Conference said Tuesday in a statement that this will show the solidarity of all dioceses toward Paris and that the fire at Notre Dame "is a shock that affects far beyond just the Catholics of our country."
France counts 103 Catholic cathedrals.
France's culture minister says the "most precious treasures" of Paris' Notre Dame cathedral have been saved after a devastating fire, including the crown of thorns Catholic relic and the tunic of Saint Louis.
Culture Minister Franck Riester told reporters outside Notre Dame that other works are being transferred from a storeroom in City Hall to the Louvre on Tuesday and Wednesday. There they will be dehumidified, protected and eventually restored.
He said that the cathedral's greatest paintings will be removed starting Friday. He said, "We assume they have not been damaged by the fire but there will eventually be damage from the smoke."
Monday's fire destroyed the cathedral roof and collapsed the spire.
European Union chief Donald Tusk says the message of encouragement to France after the Notre Dame cathedral fire should be that "it's not the end of the world" and that the damage will be repaired.
Tusk told Polish reporters Tuesday in Strasbourg after a European Parliament debate on Brexit that it was the duty of all Europeans and all Poles to give France courage after this "dramatic" event.
Recalling his native Poland's efforts to rebuild its cities, many reduced to rubble, after World War II, Tusk said that his compatriots "have the right and the duty to say — You will manage, this is not the end of the world."
The director of UNESCO says expert work must be carried out immediately to protect Notre Dame Cathedral's remaining structure after a devastating fire.
Audrey Azoulay told The Associated Press on Tuesday that it's too early to say whether the treasured rose windows of Notre Dame are unscathed because art experts haven't been able to study the site yet after Monday's apparently accidental fire.
She said "the first 24, 48 hours" are crucial to protecting the stone and wood structure from water damage and assessing next steps. She warned that parts of the cathedral remain "extremely fragile," notably hundreds of tons of scaffolding set up around the cathedral spire that collapsed.
She said Notre Dame has "a particular place in the world's collective imagination." Notre Dame is part of a UNESCO heritage site that includes the surrounding quais and islands, and UNESCO has offered its expertise to help rebuild.
Jean-Marc Fournier, the chaplain of Paris fire brigade, is being hailed as a hero after taking part in the recovery of the crown of thorns at Notre Dame cathedral.
Speaking to reporters at the cathedral, Paris' 15th district mayor Philippe Goujon said Tuesday that Fournier insisted on being allowed to enter the edifice with fire fighters and played a role in the relic's rescue.
Fournier's bravery had been noted already after the Nov. 2015 Bataclan attack, when he tended to the injured and prayed over the dead.
According to an interview he gave to Christian Family magazine after that attack, Fournier was based in Germany and in the western Sarthe region, before joining the Paris fire brigade.
He also served in the Diocese of the French Armed Forces and was based for a time in Afghanistan.
Pope Francis is offering his prayers that Notre Dame, the "architectural gem of a collective memory," will once again be a shrine to the Catholic faith, a symbol of the French nation and a spiritual and architectural gift to humanity.
In a heartfelt note of condolences sent to Paris Archbishop Michel Aupetit, Francis said Tuesday that the fire was particularly devastating given that it came during Holy Week, the somber days leading up to Easter during which Christians commemorate the death and resurrection of Jesus Christ.
Francis wrote: "This catastrophe has gravely harmed a historic building. But I am aware that it has also affected a national symbol dear to the heart of Parisians and all French people in the diversity of their convictions. Because Notre Dame is the architectural gem of a collective memory, a place of gathering for great events, a witness of the faith and prayer of Catholics in the heart of the city."
Francis praised the courage of the firefighters and invoked his blessings on the nation.
The chief architect of Cologne cathedral says it could take decades to repair the damage caused to the Notre Dame cathedral by a massive fire.
Peter Fuessenich, who oversees all construction work for the Gothic cathedral in the German city, told broadcaster RTL on Tuesday that "it will certainly take years, perhaps even decades, until the last damage caused by this terrible fire will be completely repaired."
Cologne cathedral was heavily damaged during World War II and work to repair it is still ongoing more than 70 years later.
Fuessenich called the fire in Paris "a tragedy with a European dimension" as many churches and cathedrals across the continent were inspired by buildings in France. He said that "when the last stone was set in Notre-Dame, the first one was laid here in Cologne, and in this respect it affects us all very much."
According to Fuessenich, the timbered roof of Cologne cathedral's was replaced with an iron frame during the 19th century, meaning a fire there would be less devastating.
A representative of one of the five companies which had been hired to work on renovations to the Notre Dame cathedral's roof says "we want more than anyone for light to be shed on the origin of this drama."
Julien le Bras' company has 12 workers involved in the refurbishment, though none were on site at the time of the fire.
Le Bras insisted that "all the security measures were respected," and "workers are participating in the investigation with no hesitation."
Various officials have suggested the fire could have been linked to the renovation work.
Paris prosecutor Remy Heitz said the investigation is in its early stages and is focusing on hearings while the site is being secured.
Queen Elizabeth II has sent a message of sympathy to French President Emmanuel Macron after a fire ravaged Notre Dame cathedral in Paris.
The British monarch says she was "deeply saddened" to see the cathedral ablaze, and expressed "sincere admiration to the emergency services who have risked their lives to try to save this important national monument."
British politicians and religious leaders have also sent messages of goodwill and offers of help in rebuilding the medieval building.
Archbishop of Canterbury Justin Welby, head of the Church of England, tweeted an image of the fire-damaged cathedral with a passage from the Bible: "The light shines in the darkness, and the darkness has not overcome it.'"
The Vatican's culture minister has offered words of hope to France following the devastating fire at Notre Dame, saying the cathedral is a "living creature" that has been reborn before and will continue to be the "beating heart" of France.
Cardinal Gianfranco Ravasi opened a Vatican press conference with a personal reflection on the cathedral. He noted it was a place of encounter for both believers and nonbelievers drawn to its beauty and in some cases, such as the 19th century French poet Paul Claudel, were converted to the Catholic faith as a result.
Ravasi, whose office oversees the patrimony of the Catholic Church worldwide, said he was moved by the scenes of faithful and tourists alike weeping as Notre Dame went up in flames.
He suggested that the Vatican, particularly its art experts at the Vatican Museums, could play a possible role in the rebuilding given their expertise.
The Paris prosecutor says there's no evidence of arson in the Notre Dame fire and that they're working on the assumption that the blaze was an accident.
Remy Heitz says the investigation will be "long and complex."
Speaking Tuesday, after the blaze was put out, he said 50 investigators are working on the probe. He says they will be interviewing workers from five companies that had been hired to work on renovations to the cathedral's roof, which was being repaired before the fire and which is where the flames first broke out.
This version corrects that 50 investigators are working on the probe, not five.
An aide says that Poland's president, Andrzej Duda, has offered assistance and Polish specialists for the task of rebuilding Paris' Notre Dame cathedral that was damaged by fire.
Krzysztof Szczerski said Tuesday that Duda has written to French President Emmanuel Macron to express Poland's grief and solidarity at the loss of heritage and cultural identity.
He said that in a gesture of "European solidarity" Duda offered Poland's experience and world-class experts in the reconstruction of historic buildings. Warsaw and many other places were rebuilt from World War II rubble.
He said that a Polish chapel at the cathedral was affected by the fire but was not damaged.
A precious copy of Poland's most revered icon as well as relicts of Polish-born pope St. John Paul II have been rescued.
Germany's foreign minister says his country is prepared to help with the rebuilding of Notre Dame cathedral after a devastating fire.
Heiko Maas wrote on Twitter that French President Emmanuel Macron has called for help from outside France and "Germany stands ready to do that in close friendship."
Maas added that "we are united in sorrow. Notre Dame is part of the cultural heritage of mankind and a symbol for Europe."
Egypt's top Muslim cleric has expressed sadness over the fire that destroyed part of the famous Notre Dame cathedral in Paris, describing it as a "historic architectural masterpiece."
Sheikh Ahmed al-Tayeb, the grand imam of Al-Azhar, the Sunni Muslim world's seat of learning, wrote on Facebook: "Our hearts are with our brothers in France."
Paris' deputy mayor says Notre Dame's organ, among the world's most famous and biggest, remains intact after a devastating fire at Paris' main cathedral.
Emmanuel Gregoire told BFMTV Tuesday that a plan to protect Notre Dame's treasures was rapidly and successfully activated.
The impressive organ dates to the 1730s and was constructed by Francois Thierry. It boasts an estimated 8,000 pipes.
Gregoire also described "enormous relief" at the salvaging of pieces such as the purported Crown of Christ.
Egypt's Coptic Church has expressed "profound sadness" over the massive blaze that burned parts of the Notre Dame cathedral in Paris.
The head of Egypt's Copts, Pope Tawadroz II, said in a statement that the fire was a "huge loss for entire humanity" and affected "one of the most important monuments in the world."
The Foreign Ministry in Cairo also expressed "great regret and pain" over the fire, citing Notre Dame's "historical and culture value" for France and world heritage.
Pope Francis is praying for French Catholics and the Parisian population "under the shock of the terrible fire" that ravaged the Notre Dame cathedral.
Vatican spokesman Alessandro Gisotti said on Twitter on Tuesday that the pope "is close to France" and that he is offering prayers "for all those who are trying to cope with this dramatic situation."
The Vatican on Monday expressed "shock and sadness" at the fire that caused extensive damage to a cathedral that is "a symbol of Christianity in France and in the world."
Funding for the reconstruction of Notre Dame is piling up at a spectacular rate, with two of France's richest families together quickly pledging 300 million euros.
Businessman Francois-Henri Pinault and his billionaire father Francois Pinault said they were immediately giving 100 million euros from their company, Artemis, to help finance repairs to the cathedral devastated by fire Monday night.
A statement from Francois-Henri Pinault said: "This tragedy impacts all French people" and "everyone wants to restore life as quickly as possible to this jewel of our heritage."
That donation was then trumped by French tycoon Bernard Arnault and his luxury goods group LVMH, which pledged 200 million euros.
LVMH called the cathedral a "symbol of France, its heritage and its unity."
European Union chief Donald Tusk is calling on the bloc's member countries to help France rebuild the fire-ravaged Notre Dame cathedral saying the site in Paris is a symbol of what binds Europe together.
Tusk, who chairs summits of EU national leaders, told lawmakers Tuesday that the blaze reminds Europeans of "how much we can lose."
Tusk said: "At stake here is something more than just material help. The burning of the Notre Dame cathedral has again made us aware that we are bound by something more important and more profound than treaties."
Parliament President Antonio Tajani invited EU lawmakers, meeting in Strasbourg, France, to contribute their day's salary to help finance reconstruction.
A spokesman for Paris firefighters says that "the entire fire is out" at Notre Dame cathedral.
Gabriel Plus said Tuesday morning that emergency services are currently "surveying the movement of the structures and extinguishing smoldering residues."
Plus said that now the fire is out "this phase is for the experts" to plan how to consolidate the edifice.
French tycoon Bernard Arnault and his luxury goods group LVMH have pledged 200 million euros ($226 million) for the reconstruction of Notre Dame, following a reported 100 million-euro donation from another French billionaire, Francois Pinault.
A statement Tuesday from LVMH said the luxury goods group and the Arnault family would make the donation to a rebuilding fund for the cathedral, which was consumed by flames Monday evening.
LVMH called the cathedral a "symbol of France, its heritage and its unity."
The Pinault family's earlier 100 million-euro donation was widely reported by French media.
A French cultural heritage expert says France no longer has trees big enough to replace ancient wooden beams that burned in the Notre Dame fire.
Bertrand de Feydeau, vice president of preservation group Fondation du Patrimoine, told France Info radio that the wooden roof that went up in flames was built with beams more than 800 years ago from primal forests.
Speaking Tuesday, he said the cathedral's roof cannot be rebuilt exactly as it was before the fire because "we don't, at the moment, have trees on our territory of the size that were cut in the 13th century."
He said the restoration work will have to use new technologies to rebuild the roof.
Experts are assessing the blackened shell of Paris' iconic Notre Dame cathedral to establish next steps to save what remains after a devastating fire destroyed much of the almost 900-year-old building.
With the fire that broke out Monday evening and quickly consumed the cathedral now under control, attention is turning to ensuring the structural integrity of the remaining building.
Junior Interior Minister Laurent Nunez announced that architects and other experts would meet at the cathedral early Tuesday "to determine if the structure is stable and if the firefighters can go inside to continue their work."
Officials consider the fire an accident, possibly as a result of restoration work taking place at the global architectural treasure, but that news has done nothing to ease the national mourning.