It isn't a civilian arms...it is described as the M1754 oficer's fuzee. (I'm not familiar enough with them to make a judgement but it looks right.) If so, it's an exceedingly rare French military arm. Unlike the British, fuzees were specified by pattern for junior officers in the French Army. They may have been issued...again, I doubt any of the pertinent records, if they exist, have been translated into English and I don't read French very well.
In any case, I've only seen pictures of one other and those were taken in the late 1920s.