According to the BFMTV channel, the detained man in a 39-year-old migrant who worked as a volunteer in the cathedral and was in change of locking the building on the eve of the fire.

Prosecutors told the TV channel that they had detained the man only for checking "clashes in his schedule."

The fire at the large gothic cathedral began on Saturday morning and required the mobilization of over 100 firefighters to defeat it. An investigation was launched into possible arson shortly thereafter.

The fire destroyed a 400-year-old organ, but the building itself remains intact and is not at risk of collapsing.