Notre Dame, which was built in the 12th and 13th centuries, receives around 13 million visitors each year — even more than the Eiffel Tower. The cathedral is regarded as one of the finest examples of French Gothic architecture and sits at the heart of the nation's history.

"If you think of France as a body, then Notre Dame is in many ways its heart … Its partial loss is a terrible blow to a proud country and to the world more widely," Macfarlane said.

The Cambridge professor said rebuilding efforts will pose a huge challenge, but he remains optimistic as the main structure has survived.

"It is an immense building and the result of centuries of fine craftsmanship," he said.

"But as the structure, made of stone, has survived, so it is as if a body had been badly damaged, but the legs, trunk, arms and even head are still there. Modern techniques of restoration are amazing and it is probable that what has to be replaced is well documented. With patience, money and care it can be done, and though it will not be the same, it will be Notre Dame."

A woman named Marie, who has lived in Paris for 20 years and works at an art gallery, said,"Paris without Notre Dame is not Paris."

Han Baoyi in Paris contributed to this story.