The cause was probably a discarded Gitanes, and a piff poor fire alarm system contributed. The electrics is always blamed when the real cause can not be proven. Why didn't The Almighty make it rain? He did in Noah's time.
Either way there is a lot more to this than a f** end or a short circuit.
Anyone who has tried to light a fire knows that it is very difficult unless you have some tinder, (easily lit material), then some small flammable material like twigs, then some larger flammable stuff. All this needs to be alight and in some quantity before you have a chance of getting a beam the size of a roof timber to catch fire.
Rather annoyingly, google.fr doesn't come up with any very recent local info. What does seem to have been established is that the fire started near the base of the spire, from which it could spread to all four roofs. I have heard, but not verified, is that there might have been a fault in a builder's lift. Do they have AFDDs in France? ?
This example describes the consequences of the actions of a couple of decorative lead workers, who left quickly for a tea-break without waiting to ensure that their hot work had not created an incipient fire. At a later time I worked for this company for over a decade and a close colleague was the manager responsible for that area at the time of the fire. This type of work was a very minor side line, taken up initially in one branch to keep a couple of plumbers busy between major contracts. https://www.independent.co.uk/news/world/law-report-subcontractor-is-judged-liable-for-fire-damage-to-uppark-house-national-trust-v-haden-1379674.html
