As the wooden rafters burned, the roof, a spire, and much of the cathedral’s interior were destroyed.
But some parts of the 850-year-old Gothic building have also been saved.
From rose windows to gargoyles, from bells to relics, we look at what makes the Notre-Dame cathedral so special.
Prime Minister Scott Morrison recalls his visit to the iconic Parisian cathedral
More from the French president:
“Notre-Dame is our history, our
literature, part of our psyche, the place of all our great events,
our epidemics, our wars… the epicentre of our
burning, and I know the sadness, and this tremor felt by so many fellow French people.
But tonight, I’d like to speak of hope too.
“Let’s be proud,
because we built this cathedral more than 800 years ago, we’ve built it and, throughout
the centuries, let it grow, and improved it.
“So I solemnly say
tonight: we will rebuild
Images have emerged showing a different view of the damage caused to the cathedral – including a hole reportedly beneath where the spire was positioned.
The BBC’s Neil Henderson has also been sharing some of tomorrow’s French and British newspaper front pages on social media – with the Notre-Dame blaze dominating the news agenda.
La Croix, a French Roman Catholic newspaper, has released images of its front page for Tuesday.
Former French President Nicolas Sarkozy tweeted to say that France was “touched in its heart, in its identity, in its history”.
More from the BBC’s Henri Astier, himself a Parisian:
It is impossible to overstate how shocking it is to watch such an enduring embodiment of our country burn.
Locals are not famous for their sunny disposition, but few can walk along the banks of the Seine in the central part of the capital without feeling their spirits rise at the majestic bulk of Notre-Dame.
It is one of the few sights sure to make a Parisian feel good about living there.
Further to its earlier announcement, the office says it is investigating “accidental destruction by fire”.
Mr Macron also expressed sympathy towards Catholics around the world.
“What’s happened this evening is obviously a terrible drama,” he said.
“[Emergency services fought the fire] with extreme courage, professionalism and determination… I would like to thank them on behalf of the entire nation.
“This is our history, and it’s burning.”
Speaking at the scene in Paris, President Macron called the fire a “terrible tragedy”, but added that the worst had been avoided.
He said he planned to launch a fundraising campaign to renovate the cathedral.
“We will rebuild Notre-Dame.”
While there are fears for the many priceless artworks and artefacts housed inside the cathedral, the rector of Notre-Dame, Patrick Jacquin, has told local press that the Crown of Thorns and the Tunic of St Louis have both been recovered.
French Deputy Interior Minister Laurent Nunez has announced that the fire has “decreased in intensity” and “the structure of the building is saved, including the north tower.”
Copyright: Getty Images
Radio France journalist Alexandre Fremont has tweeted an image captured by a drone flown above the cathedral, reportedly showing significant damage.
A French firefighting official has told Reuters that one fireman has been seriously injured tackling the blaze.
Footage posted on social media shows crowds of people singing as they witness Notre-Dame burning.
Reuters news agency is quoting an official with the French firefighting team as saying: “We can now say that the structure of Notre-Dame has been saved from total destruction”.
AFP is also reporting that the main structure has been “saved and preserved”, citing an official.