Noooo not French BB, my worst nightmare. I fighted for years with the BB of Mercier I fixed it with a Velo-Orange Cartridge BB. I think I saw near the BB Shell a label saying it's a canadian made (I might be wrong, getting mix up with all bike I own) I'll try Andrew method to figure if it's French or not. When I tried the stein tool and the park wrench the 36mm wrench kinda grind the over the BB Shell.
I also squirt some product to remove the rust that the hardware guy told me it was better that wd-40 for that. Can't remember the name something like rustallgone or something like that.
thanks for the info I'll keep up updated on the status