Welcome to the forum , adrien .
What you have appears to be the works of an automaton .
From around the 1600's through the 1800's automata were produced and displayed in a variety of countries .
In the 1800's , the devices were often considered a rather expensive adult 'Parlor' amusement .
Such designers as Maillard , Jacques De Vaucanson , Pierre Jaquet-Doz , Joseph Faber and George Moore made famous automata .
There are still 3 examples of the excellent work of Jaquet-Doz (the Drauftsman , the Musician & the Writer) that are in the museum of Art & History in Switzerland .
The 19th century was more or less the hey-day for production of such items that fascinated many folks .
I'd like to comment that yours might just be one that would be worthy of restoration to it's working state , if another identical one can be found (to figure out what parts are missing & can be duplicated) .
Thanks for posting your very cool item on the forum !