780 years is not that bad for a building. (or, more precisely, the roof frame)

Macron & co had some idea for new things. They were all horrible. While I do think with good taste one could do some new things nicely ( e.g maybe a titanium-based roof instead of the lead one ), a restoration is the next best choice when proposed new things are crazy ugly/out-of-touch.

Btw, in our age, and since at least the early middle-age in France and old Europe, the use of old, large trees is the main political reason to keep alive some old, large forest with old trees. For ordinary wood they do plantations of fast-growing stuff and cut at maybe 40y or so.