That little half grip is also very typically French. The photo of the top lever, with the "stop" on the L side for the lever, makes me think that it might well be made on the old Verney-Carron "Helice" system. The French think highly of those guns. A lot of makers (named and nameless) copied the Helice bolting after the patent expired.

Quite plain, but nice condition! Enjoy it, Argo.