I’m confused as to how ND could legally require it. The copyright on the structure and the art it displays as surely lapsed by now. I’m assuming this is one of those ‘the law is different in Europe’ things. Is it a Moral Authority Is Asserted thing?
Here in Phily, due to changes in the rules based on advances in technology, I am allowed to take photographs of any public domain work in the art museum and do with them as I please.
The night time art display on the Eiffel Tower (the flashing lights) is protected by copyright. So you can photograph it, but not use it for publicity. I’m not aware of anything similar for Notre Dame.
I don’t know post-fire, but ND is used as an example of this principle in the write-ups I’ve read. In good news (for me), I’ve altered my photo to an extent that it’s clearly art rather than documentation.