I'd say post-1924. The little squiggle under the PT, on both the barrel flats and the water table, looks to me like the "supplementary mark for definitive proof in completely finished state". That's not a mark you see on many French doubles, and it's one that is more helpful in dating the gun.
Lots of nice French phrases as well, but most are basically meaningless--more like advertising than anything else. The range is guaranteed (but they don't tell you what it is). The choke's been adjusted (but they don't tell you what it is). And the barrels are made of "safety steel", whatever that is. Looks to be your basic French guild gun, which--as noted above--is not bad news at all, but rather good news because they're pretty solid products. You may find that trigger pulls are quite heavy. That, in addition to a whole lot of choke, is perhaps the major problem I've found with vintage French doubles.
