So, in light of there being a boon in construction because of the 2024 Olympics, a lot of construction companies are in high gear, doing a lot of renovations, bids, ect. And so they may be busier than ever, getting as much work lined up to make Paris a nice city to host the Olympics.
So, you can see how in the hustle and bustle to meet a deadline - granted it is five years off - there is a lot of anticipation and preparations going on. And construction firms have a long roster of contracts that will keep them busy till 2024.
So, it's very busy for construction.
And as things are very busy, workers are overworked. And accidents happen.
Since Notre Dame is a big attraction, you can guess how much it is a consideration in the Paris 2024 Olympics. So, it's renovation must have been bolstered by the fact that the Olympics were coming. Maybe there were designs to change the cathedral to make it a Olympics friendly attraction.
Anyway, lots of work, it's a Monday, and it is the middle of the month, so it may have been a payday, and since Easter was a week away workers had to work around the church schedule. So, at the end of the day, they want to go cash their paycheck, have a beer, go to the cabaret, ect. A tired worker flicked their cigarette on the way out and the rest is history.