I have one in poor condition, a strange gun, some of the inner parts are "jeweled", or "engine turned", the decorative spot finishing that we sometimes see on rifle bolts.
The value of your gun is relative only to nut cases like me who collect unusual guns, if I were to come across one in that shape I'd go as high a $250 for it, but my collection is very general. Someone collecting French pocket pistols might go higher, and the condition may mean as high as $400-$600.
Doubtless a large number of modern handgunners wouldn't give anything for such a gun, but such people speak of plastic guns as if they are real guns in the same league as a pristine 1911 too, so I wouldn't be concerned about that.
You have a real treasure there, have you fired it? If it appears to be unfired I wouldn't, you can get as much "shooter" pleasure from shooting any small .25 that won't lose a huge chunk of it's value by doing so.