From CNN:

An arson investigation has being launched into a fire that broke out in a cathedral in the western French city of Nantes on Saturday, the city’s Mayor Johanna Rolland told CNN affiliate BFM.

“What is certain is that there were three different fire outbreaks, I saw them myself,” Rolland said about the blaze at Cathedral of Saint Peter and Saint Paul, which has been contained. CNN has contacted the Nantes prosecutor’s office for more information.

Fire Chief Laurent Ferlay told a press briefing in front of the cathedral that the blaze was not as big as the one that engulfed Notre Dame Cathedral in April 2019, and the damage is not as bad.

“I can confirm that we are not in the Notre Dame of Paris situation, rooftop is not affected,” Ferlay told CNN affiliate BFM on Saturday.

“The damage is concentrated on the organ, which seems to be completely destroyed. Its platform is very unstable and could collapse,” he said.

Ferlay added there are 104 firefighters at the scene, who will remain there “all day.”

Images and videos from the scene showed orange flames and smoke billowing out of the front windows of the soaring Gothic structure.

French President Emmanuel Macron tweeted his “support” of the firefighters who contained the fire on Saturday.

“After Notre-Dame, the Saint-Pierre-et-Saint-Paul cathedral, in the heart of Nantes, is in flames. Support to our firefighters who take all risks to save this Gothic gem of the city of the Dukes,” Macron wrote.

Read more.

About the cathedral:

Construction of the church began in 1434, on the site of a Romanesque cathedral, and took 457 years to finish, finally reaching completion in 1891. It has been listed since 1862 as a monument historique by the French Ministry of Culture.

…The edifice was damaged by Allied bombing during World War II, on 15 June 1944. On 28 January 1972, a gigantic fire started on the roof. Firemen managed to bring it under control, but the timber frame was severely damaged and many other damages were inflicted. This event led to what was undoubtedly the most complete interior restoration of a cathedral in France.

Some context, from an essay published in The Spectator last January:

In 2017 alone, according to France’s Interior Ministry, 878 acts of vandalism were committed against Christian places of worship, cemeteries and shrines. That’s an average of nearly two and a half sites being targeted every day.

Government officials play down the problem. As one French bishop told me, they believe that directing attention to church burnings and theft could encourage copycat behavior. But, he added, they also fear publicity might fuel an existing concern among the population: that the state isn’t fully in control of law and order. This perception is underscored by realities such as no-go areas for the police in some French cities and ongoing gilets jaunes protests. Most French newspapers have acquiesced in this silence. That’s why you need to turn to organizations like the Vienna-based Observatory on Intolerance and Discrimination against Christians in Europe to discover what’s going on.

Given the surge in jihadist terrorism throughout France from 2012 onward, it’s tempting to blame Islamists for this onslaught of attacks. There are clear examples where this is the case. Last May, ‘Allahu Akbar!’ was scrawled across the door of Notre-Dame du Taur in Toulouse. In July 2018, the same words were discovered on the burnt walls of Saint-Pierre du Martroi in Orléans after it was damaged by arsonists.

Whether these and similar attacks were professionally planned or simply spontaneous acts by French Muslims unhappy with their lot in life is unclear, but 21st-century jihadists understand the psychological impact of assaults on national symbols. France’s particular religious history means that any such campaign would inevitably involve its Christian patrimony.

Other cases, however, indicate that some attacks have other causes which are less easy to categorize.