The state hasn’t offered hundreds of millions. The top French billionnaires did.
The same billionnaires who are regularly in the news because of their tax evading habit.
And chances are that the generous donation will be deductible from what little tax they pay, and they will also get a nice plaque with their names in the newly rebuilt Notre Dame, because they are such upstanding citizens.
Shame they couldn’t be bothered to pay for, in part, the firefighters who actually saved the building.
(Not to mention schools, hospitals, train services… anything usually to do with the plebs, those silly people who do pay their taxes)
From the Notre-Dame website, the most recent renovations were
1965 : stained-glass windows refurbished
1990-1992 : renovation of the pipe organ, and then cleaning of the façade
in the 2000s, there was some change to the organisation on the floor.
So mostly just for show, nothing seems to have to do with safety.
There had been a call for donations for renovations which raised 150 millions, and they had just started after some months spent installing scaffolding very carefully. Those might have had some impact on safety, but I do not know if a sprinkler system was considered. It might be now that there is a lot of room to work with.
The responsibility for lack of care may be a bit of a mess administratively speaking, as it looks like both Church and State are involved.
Apparently the cathedral wasn’t insured, because for such religious buildings, built before 1905, the State is its own insurer [meaning they aren’t insured] (A decision dating back to 1889, apparenly. Following a few storms in the late 1990s/early 2000s, a report pointed out that maybe it should be revised.)
Edit: the Architectes des Bâtiments de France may also be involved in whatever renovations happen, and may decide that some things cannot be done to certain listed buildings.