French President Emmanuel Macron says Notre-Dame cathedral will be rebuilt "even more beautifully" - and that he wants the work done within five years, BBC reports.
But despite Mr Macron's pledge experts say its reconstruction could take decades.
Fifty people will investigate the cause of the fire. Paris public prosecutor Rémy Heitz said there was no obvious indication of arson and that the blaze was being treated as an accident.
A combined €800m ($902m; £692m) has already been pledged by a number of companies and business tycoons to help rebuild the Unesco World Heritage site.
In a televised address on Tuesday evening, President Macron suggested he wants it rebuilt by the time Paris hosts the Summer Olympics in 2024.
"We'll rebuild Notre-Dame even more beautifully and I want it to be completed in five years, we can do it," said Mr Macron, who had already pledged to launch an international fundraising scheme for the reconstruction.