Detained again on the weekend for further questioning,the worker whose name was not released admitted responsibility for the fire,said his lawyer,Quentin Chabert.
"He confessed to the allegations against him which,as the prosecutor indicated,are causing destruction and damage by fire,"the lawyer told France Info radio."He regrets the facts. That is certain. He is in a sort of repentance."
French media quoted the Nantes prosecutor as saying that the 39-year-old Rwandan,who'd been tasked with the job of locking up the cathedral,told the investigating magistrate that he lit three fires:on two cathedral organs and an electrical box. His motives were unknown.
Asked why his client had set the fires,Chabert declined to elaborate.
The prosecutor said the arson charge is punishable by a 10-year jail term and a fine of €150,000 ($246,000).
Picked up immediately after the fire,held for over a day and then released,the man was detained again on Saturday morning,on the basis of evidence gathered by police forensic experts and a 20-strong team of investigators who questioned more than 30 people,the prosecutor said in a statement.