"Megots" aka butts were discovered at Notre Dame de Paris. Somewhat OT but definitely related to large construction projects and public works and resulting accidents and liabilities. Medieval construction did not have to deal with smoking workers. A fire breaking out in the area being restored not long after the end of the working day is totally consistent with the smoldering ash theory.

Some want to rebuild with original materials, i.e. oak(les chenes) but I suggest that is a mistake. You would be recreating a firetrap which you plan to send thousands of tourist thru every day. Better concrete or metal ribs for the vault. It is going to be a Disneyland-Vegas replica anyway as the original and historical is cinders.

Some cities are pulling back their donations because there is already around a billion in funds promised. France has many historical sites that are in advanced deterioration and need the money locally.