The one in your image is a Belgian made copy of the Lefaucheux model 1854. And based on the super clear image you can see it has the next on the side which likely says "E. Lefaucheux Inv. Breveté" which is what was required when they paid royalties to Lefaucheux.
The Belgian ones have this 2-piece frame that is screwed together in the front like:
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Where as Lefaucheux's have a single piece frame:
There are other difference too such as the markings and other smaller differences which are easy to see in person, but even in pictures you can tell pretty easily from this aspect.
And in additional to the LF marking in front of the cylinder, they also hae different wording, in a different spot on the other side:
"Invention Lefaucheux Breveté SGDG Paris" or "Inv. E.LEFAUCHEUX BREVT SGDG PARIS" or similar.
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