This style of 19th Century pistol was called 'coup de poing' in France, where it originated, which translates to 'fist blow' in English.
Its long, fluted cylinder is a modified pepperbox design made from a single piece of metal, and the front end of the cylinder axis pin is supported by a bracket screwed to the front end of the lower frame. The breech consists of a thick, flat, circular plate with a semi-circular opening cut out on the right-hand side so that the weapon could be loaded from the breech end. This opening is filled by a bottom-hinged gate shaped to match the circular breech block, which is held closed by a small, horizontal, L-shaped spring lever screwed below it on the frame.
There is an additional shallow depression on top of the breech block, where the hammer rests. Its trigger action is basically that of a double-action revolver, where pulling the trigger cocks the hammer and rotates the cylinder. The cylinder was normally free to rotate, but when the trigger was pressed a cylinder-stop rose from the lower frame and engaged one of the studs which can be seen on the cylinder. When loaded, the cylinder could be positioned so that there was a pin on each side of the hammer head, making it relatively safe to carry the loaded weapon in a pocket. Once the rounds had been fired, the empty cases could be pushed out through the open loading gate by means of a separate extractor pin.