This is a “pistol of secretary”, i.e. a booby-trap, a trap which one could install a little everywhere to protect a cupboard, a room, etc
It is very rare and extremely interesting.
The lever under the barrel, with the small caster, is the system of release of remote shooting by wire of thrust.
Look at the photographs.
The back key is used to fix the trap in the desired position.
The barrel is striped, but charged with buckshots, this thing can make solids damage…
Who manufactured? Mystery, but there was to be more than one manufacturer of these objects. There are of them one or two in “4 centuries of Arms manufacture of Liège” if I’m not mistaken.
One could charge these weapons with white, to make noise, or with chicken feathers; but charged with buckshots they were frightening.
You open the door, and you could put new paper on the walls of the chamber. Bang, in other words.
There does exist badly of other less elaborate models, in general just a barrel and a hammer fixed on a metal plate, but also with a system of release per wire of obstinate (tension or relaxation of tension).
Sudesh......