I find it hard to believe in this day and age that a building like Notre Dame isn’t surveilled from multiple angles.
Look at the Jussie surveillance. They had him from point a to point b almost completely.
Western big cities have become panopticons.
We’re on a need to know basis and the powers that be have decided we don’t need to know.
Can we remove the tinfoil, or at least loosen it up a bit ?? You have work being done IN an 800+ year old structure, 30 meters off the ground. not many surveillance cameras pointing skyward, nor inside he roof of Notre Dame. They are erecting the scaffolding, running generator electric into a tightly confined space, so figure a bunch of dust. You probably have lots of electrical connections, welders, cutsaws, and acetylene torches. There is more then just the oak support timbers,, the spire is made of 200 year old wood, the actual roof is wood (planking) supporting lead tiles.
There were all kinds of combustibles, and all kinds of ignition sources. Keep in mind that worksite electrical connections gets bashed around a bit. So an electrical connection shorting out or stay spark from another source and you have an accidental fire. Probability 99.9%
Achmed either working at or breaking into a busy worksite and accessing the inside of the spire/roof area where the fire started .1%