AFAIK, unlike Belgian, Austrian and German guns, other than checking for changes in the other proof marks and correlating that to a range of dates there is no particular way of telling which year a French gun went through proof. I.e., the French didn't stamp specifically for year like the Belgians and Austrians or year and month like the Germans.

From the looks of the barrels, best guess would be the inter-war years, probably earlier rather than later.

fiery, dependable, occasionally transcendent