16 ga (17.0 - bore in mm), 2 1/2 inch ("65"), opened to 2 3/4 ("16/70") in Germany (that's a German 16/70 stamp) and reproofed in Suhl August '43, shield (for Suhl) and two eagles (Eagle +J = repair, Eagle +N = nitro proof), then the date ("843"). Proofed after opening the chambers, thus, the "repair" proof. Probably "Beute" - booty - taken back to Germany during Occupation, possibly from the factory/retailer, and had to be reproofed before entering the stream of commerce.
I'm willing to bet that if it hasn't been sanded off at some point, there will be a monogram-ish "SuS" stamp somewhere, probably not that conspicuous, on the buttstock. You'll have to look closely. That SuS would be the logo of Sauer Und Sohn (Sauer and Son). Every one of these "back-to-Germany" French guns I've seen has had the SuS stamp somewhere. I speculate Sauer had a deal (probably as a contractor with expertise in this field) with the then-government(s) of Germany (and possibly France, possibly Vichy - don't know whether St. Etienne was in Vichy or not) to take over and distribute/sell these French guns, possibly as some form of reparations/payment in kind for the occupation. If St. Etienne was in Vichy, in 1940 this gun may have been in process under an order for the retailer marked on it, and left sitting around the factory undeliverable after the events of that year, then looted to Germany sometime before August 43.
That is definitely a "J.G." on the lower rib. "JB" (as shown upthread) would be the stamp for French barrelmaker Jean Breuil. J.G., I have no idea.
Last edited by Dave in Maine; 02/27/18 06:40 PM.