A vehicle seat that accommodates at least two users includes a seating portion frame, a first backrest and a second backrest which are pivotally hinged to the seating portion frame according to a transverse axis, via a common hinge. The common hinge includes: a pivot pin comprising a first lateral portion, and a first housing arranged on the first backrest and receiving interiorly the first lateral portion by authorizing the rotation of the first backrest. The first lateral portion has a protruding rib and the first housing has a substantially keyhole shape, complementary with the radial section of the first lateral portion. The rib is oriented, according to an angle of between 30° and 60° relative to the vertical direction of the vehicle seat.