Has there been any history of fire of this magnitude at the Cathederal in the past almost 800 years? Why now all of a sudden with all the modern building codes and regulations. The construction company was well renowned and experienced. They would have taken precautions. I have a hard time believing it was an accident. How many fires break out at construction sites? Apparently there have been a number of churches vandalized by Muslims in Europe recently. I suspect many more accidental fires will start in churches in the future. These churches were safe from fires for hundreds of years but now with modern technology and building regulations they are in danger!!Apparently the entire place is loaded with sensors and dedicated staff that patrols for fire. A building of that importance is monitored like a hawk so I imagine they'd have a pretty quick idea of what caused it as opposed to a building that isn't. FWIW none of the construction crew was there so it's not like that area was teaming with people. As soon as the first alarm went off they had someone up there and judging by the photos of rafters it's not easy to get in and out of. Here's an in depth article on the building and the fire. It will be interesting to see what the cause was:
Notre-Dame Attic Was Known as ‘the Forest.’ And It Burned Like One.