Timepiece transmission mechanism with reduced coupling force

A timepiece transmission mechanism, with a differential mechanism with inputs or outputs including a first wheel set cooperating with a first train and a second wheel set cooperating with a second train, this differential mechanism kinematically connecting the first wheel set and second wheel set in the coupling position, and separating them in the uncoupling position, the first wheel set carrying a planet wheel set which meshes with a toothing of an arbor integral in rotation with the second wheel set, and with a crown-wheel forming another input or output of the differential mechanism, which includes control means arranged to lock or release the crown-wheel to perform the coupling or the uncoupling function, depending on the position given to the control means by a selector arranged to cooperate with an actuator of a timepiece movement, or to be operated by a user.