That is a fine looking piece - elegant is the appropriate word. Well, I'll likely get myself contradicted quickly. But it was my understanding that Casimir Lefaucheaux was a Parisian firm and originally used barrels from Leopold Bernard. A Paris proof house mark exists but it is almost never seen. In the line on dating early 20th Century Saint Etienne shotguns, I translated a letter from Didier Drevet to a Haut Loire newspaper in 1878 (after the Paris Universelle Exposition), in which he complained mightily about the laxity of Parisian standards, their use of Belgian gun parts and their lack of a proper proof house to regulate things saying essentially that it wasn't fair that Saint Etienne guns had to be proofed while the Parisians just skipped the whole process. I don't think it was until 1885 that regulations on proofing guns nationwide in France were passed and it wasn't mandatory until after WWII. In other words, I speculate that you're unlikely to see any real proof marks on a Parisian Lefaucheaux from this era.
I would be very tempted to post your gun on the French gun chat site "
https://www.chassepassion.net/forums. You'd be almost guaranteed to get a good answer.
