John here's what I can tell you about the French gun
Two crowns over PT means it was double proved with T powder to a minimum psi of 16,356. This also means it is post 1926
The two Xmas trees pointing at each other directly beneath the double crown over PT means it was given final proof as a finished gun (barrels blued).
The three antlers look to be some kind of maker's mark, signifying some kind of quality level, in the same way Manufrance used wreaths. Speculation on my part.
The name on the barrels is likely the name of the barrel maker....all barrels were either marked with the name of the French barrel maker or they were deemed to be imported and marked to indicate that with "arme etrangere" after proof was completed.
Proof in France has been voluntary since 1885. As a result, proofing, double proofing, triple proofing were used as marketing ploys.
Because of a mark that is not there, or at least I'm not seeing in these pics, I think the gun dates between 1926 and 1946.
Your barrel length in millimetes, barrel weight, gauge and chambers should be marked somewhere, although if they were all within standard norms, sometimes the St Etienne house would just mark "normal" The French don't mark for choke.
I can't manipulate the pics...for some reason I can't grab these and get them on my computer, so I am having a great deal of difficulty figuring out the words (names?) that are stamped in the circular pattern at the forward end of the barrel flats.
As far as who made the gun, I can't tell you if it's not on the action or the top rib. But I think this gun was made sometime between 1926 and 1946 and given that it is at least double proved, was meant to a be a "better" quality gun.
If anyone has a different interpretation, please post. Reading this stuff can be a bit of a black art and I don't see enough different French guns to really get familiar with their marks.