Well this ones a bit hard to track down. First thought is an H&R, but the grip profile and barrel seem off for them, second thought was Smith and Wesson, but again, not quite right. Then I noticed your info says Germany, which led me to think it could be an old Russian revolver. I really don't know much about them but maybe that could help your search.
Look very closely at the top and sides of the barrel.... there may be faint markings there.
Great ID! I looked at the S&Ws and was thrown off by the barrel.... Didn't cross my mind it could have been cut down.
As to it being a shooter..... I may be just a bit crazy, but if I had that pistol, I'd give it a good cleaning and oiling to remove the rust, and check it for any damage to the frame cylinder and barrel, and if I didn't find any I'd try to track down some ammo for it. I think I'd be content with light loads, but if there were no defects I'd pretty much have to shoot it at least one time. Several years ago a friend of mine came over with an Arisaka rifle his uncle brought home from the war. I cleaned it up (had been in a closet since 1946) and rummaged through my random ammo box and found 6 rounds of post war 6.5.... an hour later I fired it for the first time since the day it was dropped on Okinawa. Something about actually shooting the old guns just makes their history seem more alive to me than it does seeing them on the wall.