Vehicle seat comprising: - a seat cushion and a seat back mounted to pivot on the seat cushion about a rotation axis, the seat back having an adjustable raised position and a lowered position, - at least one articulation mechanism for adjusting the raised position of the seat back, the articulation mechanism including a casing delimiting a housing, a locking system in the housing of the casing and an operating member that can be actuated by a user, the casing having an exterior peripheral edge and a radial overall size defined by a cylindrical envelope that extends along the rotation axis and passes through the outer edge of said casing, the casing including a first flange attached to the seat cushion and a second flange attached to the seat back, the second flange being mounted on the first flange to pivot about the rotation axis, the locking system having a locked state in which said locking system prohibits pivoting of the second flange relative to the first flange and an unlocked state in which said locking system allows said pivoting, the operating member having a rest position toward which said operating member is urged and being movable toward an actuating position, the operating member being connected to the locking system in such a way that in the rest position of said operating member the locking system is in the locked state and in the actuating position of said operating member the locking system is in the unlocked state, - a neutralisation system (9; 9') allowing movement of the seat back between the raised and lowered positions, the neutralisation system (9; 9') being outside the casing of the articulation mechanism and including a neutralisation member (33; 33') that can be actuated by the user and a retaining member (40; 40'), the neutralisation member (33; 33') being movable between an inactive position in which said neutralisation member (33; 33') allows movement of the operating member between its rest and actuating positions and an active position in which said neutralisation member (33; 33') places the operating member in the actuating position, the retaining member (40; 40') being movable relative to the seat cushion between a retaining position in which said retaining member (40; 40') holds the neutralisation member (33; 33') in the active position and a retracted position away from the retaining position, said vehicle seat being characterised in that at least an essential part of the neutralisation member (33; 33') and at least an essential part of the retaining member (40; 40') are contained within the radial overall size of the casing of the articulation mechanism. - a seat cushion and a seat back mounted to pivot on the seat cushion about a rotation axis, the seat back having an adjustable raised position and a lowered position, - at least one articulation mechanism for adjusting the raised position of the seat back, the articulation mechanism including a casing delimiting a housing, a locking system in the housing of the casing and an operating member that can be actuated by a user, the casing having an exterior peripheral edge and a radial overall size defined by a cylindrical envelope that extends along the rotation axis and passes through the outer edge of said casing, the casing including a first flange attached to the seat cushion and a second flange attached to the seat back, the second flange being mounted on the first flange to pivot about the rotation axis, the locking system having a locked state in which said locking system prohibits pivoting of the second flange relative to the first flange and an unlocked state in which said locking system allows said pivoting, the operating member having a rest position toward which said operating member is urged and being movable toward an actuating position, the operating member being connected to the locking system in such a way that in the rest position of said operating member the locking system is in the locked state and in the actuating position of said operating member the locking system is in the unlocked state, - a neutralisation system (9; 9') allowing movement of the seat back between the raised and lowered positions, the neutralisation system (9; 9') being outside the casing of the articulation mechanism and including a neutralisation member (33; 33') that can be actuated by the user and a retaining member (40; 40'), the neutralisation member (33; 33') being movable between an inactive position in which said neutralisation member (33; 33') allows movement of the operating member between its rest and actuating positions and an active position in which said neutralisation member (33; 33') places the operating member in the actuating position, the retaining member (40; 40') being movable relative to the seat cushion between a retaining position in which said retaining member (40; 40') holds the neutralisation member (33; 33') in the active position and a retracted position away from the retaining position,