Notre-Dame will be rebuilt within five years and be "even more beautiful" than before, the French president vowed, as about €700m (£605m) of donations poured in for the fire-ravaged cathedral.
Emmanuel Macron said he hoped French people would pull together to rebuild the centuries-old masterpiece, a symbol of France in the heart of Paris.
Speaking to the nation on Tuesday evening, he said: We have so much to rebuild, so yes, we will rebuild the Notre-Dame cathedral, even more beautiful, and I want that to be completed from now – until five years. We can do it.
He also referred to the project as being passionately French, saying it would be something which would unite people..
It is up to us to convert this disaster into an opportunity, Mr Macron added.
World leaders and ordinary people alike expressed solidarity with the French people and shared their memories of a monument that is among the world’s top tourist attractions.
The bells at Westminster Abbey tolled at 5.43pm on Tuesday afternoon – 24 hours after the fire started – and Prime Minister Theresa May announced bells at churches and cathedrals across England would ring in a further show of solidarity on Maundy Thursday.
In Washington, White House press secretary Sarah Sanders said: Notre Dame will continue to serve as a symbol of France, including its freedom of religion and democracy.
We remember with grateful hearts the tolling of Notre Dame’s bells on September 12, 2001, in solemn recognition of the tragic September 11 attacks on American soil.
Those bells will sound again.
At least €600m (£519m) was raised to restore Notre-Dame within 24 hours of the catastrophe.
The funds come as about 30 workers tackling the renovations on the roof – where the fire started – were being questioned over the outbreak of the blaze.
French billionaire François-Henri Pinault donated €100m (£86.4m) towards efforts and was shortly followed by LVMH chief executive Bernard Arnault who offered €200m (£173m) to reconstruct the symbol of France.
Mr Pinault said: This tragedy strikes all the French and beyond all those who are attached to spiritual values. Faced with such a tragedy, everyone wants to revive this jewel of our heritage as quickly as possible.
French energy company Total will donate €100m (£86.4m), as a further €200m (£173m) was pledged by French luxury and cosmetics group L’Oreal and the Bettencourt Meyers family.
Other funding efforts are underway through crowd-funding pages and French President Emmanuel Macron announced an international fundraising campaign.
The first reports of a fire at the world-famous landmark came at 6.50pm local time on Monday. The edifice burned for more than 12 hours until the final flames could be extinguished.
Around 500 firefighters worked throughout the night to put out the flames, with two police officers and one firefighter injured during the efforts.
The Paris prosecutor said there is no evidence of arson and the current belief is that the fire was an accident.
Remy Heitz says the investigation will be long and complex and that interviews will be carried out with workers from five companies hired to work on renovations to the cathedral’s roof, which was where the fire started.
Julien le Bras’ company has 12 workers involved in the refurbishment, though none were on site at the time of the fire.
He said: We want more than anyone for light to be shed on the origin of this drama and insisted that all the security measures were respected, saying workers are participating in the investigation with no hesitation.
Despite much of the roof being damaged and the spire breaking off, emergency services managed to save the building and a number of treasures were rescued.
Frank Riester, the French culture minister, thanked emergency services and those who helped save the relics, treasures and art in the cathedral.
He said some of the items will be taken to the Louvre, the world’s largest art museum, for safe-keeping and any repair work that is needed.