By Stefan J. Bos
In a statement on social media service Twitter, the French President Emmanuel Macron wrote that "After Notre-Dame, the Saint-Pierre-et-Saint-Paul cathedral, in the heart of Nantes, is in flames. " He added: "Support for our firefighters who take all risks to save this Gothic jewel of the city."
However, firefighters brushed aside comparisons with Notre Dame cathedral in Paris, whose lead roof and spire burned down in April 2019.
But the Nantes fire brings back memories of that devastating blaze that threatened to topple the medieval monument.
The blaze came after this cathedral also suffered a severe fire in 1972.
Nantes Mayor Johanna Rolland called the building part of France's history and heritage. Saturday's blaze shattered stained glass windows and sent black smoke spewing from between its towers.
Local firefighters said the roof was not affected by the fire, which broke out earlier on Saturday. They stressed the blaze was "under control."
Authorities began investigating Saturday, who allegedly tried to torch the architectural miracle and why.
Recently appointed French Prime Minister Jean Castex and French Interior Minister Gerald Darmanin were due to visit the site late Saturday.