A device for locking a folding element in position for a vehicle seat including: a fixed element, designed to be fixed to the vehicle seat, a rotating element, designed to be fixed to the folding element, installed free to rotate relative to the fixed element about a rotation axis (X), the rotating element comprising at least a first locking structure, and a locking element, installed on the fixed element and that can be moved between a locking position in which it locks the rotating element in rotation relative to the fixed element by at least partial engagement of the locking element in the at least one first locking structure of the rotating element, and a release position in which it allows free rotation of the rotating element from the fixed element by release of the locking element in the at least one first locking structure of the rotating element.