I'd bet that this is late enough that it has British threads in the BB and HS (but not stupid enough to bet real $$, it's French, after all!). Since it's practically mint, you might be lucky and not have to open anything up for new grease, but after 25+ years, maybe that grease has turned to cement. I'm sure you could sell it for more if you list it on CL near a College: mixtes are in demand by fashion-conscious girls...at least until they discover Dutch City bikes
(the next wave in female bike fashion)