A mechanism including a magnetic gear including a first wheel, a second wheel and a third wheel. The first wheel is provided with permanent magnetic poles which are arranged so as to form the magnetised teeth of a first magnetic toothing. The second wheel and the third wheel are provided with teeth made of a soft ferromagnetic material respectively defining a second magnetic toothing and a third magnetic toothing, each with a number of teeth that is greater than that of the first magnetic toothing and having a magnetic coupling with this first magnetic toothing. The second magnetic toothing is directly coupled with the first magnetic toothing and with the third magnetic toothing thanks to the magnetic fluxes provided by the magnetised teeth of the first toothing and the teeth of the second magnetic toothing are magnetically separated from one another.