The other eight smaller bells were cast in the Normandy foundry of bell maker Paul Bergamo.

A '21st century set of bells'

"The idea of this project was to recreate a set of bells which was as great as the ones that were existing before the French revolution. It was not to recreate an old-style set, but a 21st century set of bells."

The cathedral’s bells rang for coronations and for the end of the two world wars. But some bell experts joke their clangs were so discordant they rendered deaf Quasimodo, the famous fictional Hunchback of Notre Dame.

Bergamo is more diplomatic.

You can always find some worse (bells). If it was for a medium-sized church lost in the countryside, maybe it could have been acceptable. But for the first church of France to have a set which is not one of the best sets in France is not acceptable."

A difficult task

But replacing them has not been easy. Because of France's 1905 law separating religion and state, the bells are property of the French government, not the Catholic church.

"That's probably why it took so long to replace these bells. Because it was not a priority of the state to replace these bells."

Bergamo's foundry began crafting the eight smaller bells in February 2012, relying on years of historic research and modern-day computer modeling.

"A good bell is the bells which ring well. It is a bell for the found or the casting part is a bell with a good skin, a good aspect. And, thirdly, as a symbolic object, it should be a bell where the decoration has a meaning."