Im not sure yet if this has anything to do with Muslims.....Its an old building, could very well be unrelated to Muslims. Well see.
Muslims love to burn stuff. This is a reply to the NZ mosque attack. No doubt in my mind.
Muslims have a history of burning down churches and building a mosque on that site. I guess that there are enough muslims in France that they feel that they can get away with that now.
They can burn down an earthly church or cathedral, and will have to answer for it at the White Throne Judgement, but neither they nor the gates of hell will EVER prevail against the true Church of the Lord Jesus Christ.