It is a Darne (lower grade) or a Darne copy. It will have proof marks on the bottom of the barrels if it is French made. There should be a serrated bar inside the action that, when pushed down, will release the barrels for disassembly and viewing of the proofs. If French, it will be a sound shooter and might go for, oh, say, something like $500.

More knowledgable will likely add more information.