As always, Sheldon has an article that tells you everything you need to know.
A French headset means the odd 22mm stem quill size, rather than the standard 22.2mm (7/8"). That will also normally mean 25mm bars.
Most French bottom bracket shells are 68mm width (not diameter). A shell with the MAVIC chamfer is normally fine for use with a standard bottom bracket, but of course in this case that means a French threaded unit. Retapping to BSC isn't an option, but if the shell isn't particularly flimsy, you might consider having it tapped out to Italian (36mm x 24tpi).
Those MAVIC bottom brackets are very durable though.
Calmes dans le demi-jour
Que les branches hautes font,
Pénétrons bien notre amour
De ce silence profond.