French President Emmanuel Macron is treating the fire gutting Notre Dame Cathedral as a national emergency.
Macron reached the landmark cathedral today and went straight into meetings at the nearby Paris police headquarters.
The cathedral is home to incalculable works of art and is one of the world's most famous tourist attractions.
The cause of the blaze was not known but the Notre Dame spokesman said the whole frame of the cathedral was burning.
France's civil security agency says "all means" except for water-dropping aircraft were deployed to tackle the blaze.
The defence agency said those were unsuitable for fires like the one at Notre Dame because dumping water on the building could cause the whole structure to collapse.
Mr Macron says the fire is taking part of everyone in France with it. Macron tweeted after the blaze broke out in the cathedral's spire on he was sad to see "a part of us being on fire."
He extended "thoughts for all the Catholics and all the French."