A donation page has been set up to raise money for the restoration of Notre Dame.
The iconic 800-year-old cathedral caught on fire yesterday in Paris, with video footage showing the moment its spire collapsed amid the flames.
The roof was also damaged but the bell towers were spared.
More than €2 million (£1.7m) has been raised in less than 24 hours for the rebuild through an official website.
A total of £345m had already been pledged for the reconstruction.
Bernard Arnault, the chief executive of LVMH, which owns fashion houses including Louis Vuitton, Christian Dior and Marc Jacobs, said his family and the LVMH Group would donate €200 million (£173 million) to the fund for the reconstruction.
The Pinault family pledged more than €100m (£86 million) for the rebuild and French energy firm Total announced it would also be making €100m available.
Mr Pinault told BBC Radio 4’s Today programme: ‘We need to rebuild collectively this part of our history, of our culture, so it’s an urgent, urgent need to move forward, so I decided to unlock a very important amount of money to do that.’
Firefighters announced this morning they had successfully put out the flames after 12 hours.
‘Notre Dame was destroyed but the soul of France was not,’ Archbishop of Paris Michel Aupetit said afterwards.
Paris officials confirmed the world famous 18th century organ that boasts 8,000 pipes appeared to have survived the blaze, along with other treasures inside the cathedral, after a plan to safeguard heritage was quickly put into action.
French President Emmanuel Macron pledged to rebuild the cathedral and appealed for help to do so.