The Paris fire brigade is fighting the flames after the roof collapsed on the medieval building. President Emmanuel Macron has canceled his speech to the nation. No deaths have been immediately reported. The cause of the fire was not clear, but officials say it could be connected to renovation work. Plumes of smoke are billowing around the spire of the 850-year old Gothic building. Last year, the Catholic Church in France urgently appealed for funds to save the cathedral which was starting to crumble. Millions of tourists visit the ancient Paris landmark every year. It is undergoing renovations since cracks began to appear in the stone, sparking fears that the structure could become unstable. Macron will be going to the scene of the fire, a palace spokesman said.