A locking system for a motor vehicle door leaf, the system comprising a door leaf which extends longitudinally, in a vertical plane, from a front edge to a rear edge, and a handle of the flush type comprising at least: - one chassis which is adapted to be fastened on the door leaf, - one gripping lever which comprises a gripping element, the gripping lever being movably mounted in rotation relative to the chassis about a first axis of rotation, between at least one rest position in which the gripping element is flush with an outer face of the door leaf, one active position in which the gripping element protrudes relative to the outer face of the door leaf and one open position in which the gripping lever unlocks the door leaf, - one transmission lever which delimits a first blocking face and a second blocking face, and which is pivotally mounted relative to the chassis about a second axis of rotation perpendicular to the first axis of rotation of the gripping lever, between a rest position and an actuating position in which the transmission lever actuates the opening of a lock of the door leaf, the transmission lever being driven in rotation by the gripping lever, and characterized in that it includes: - a first reversible inertial safety system which is mounted on the chassis and which includes a first rocker beam carrying a first inertia mass, first rocker beam which includes a first blocking finger and which is pivotally mounted about a third pivot axis substantially perpendicular to the second axis of rotation of the transmission lever, between a rest position and a blocking position in which the first blocking finger prevents the rotation of the transmission lever, in case of shock, - a second irreversible inertial safety system which is mounted on the chassis and which includes a second rocker beam carrying a second inertia mass, second rocker beam which includes a second blocking finger and which is pivotally mounted about a fourth pivot axis substantially parallel to the third pivot axis of the first rocker beam, between a rest position and a blocking position in which the second blocking finger prevents the rotation of the transmission lever, in case of shock. - one chassis which is adapted to be fastened on the door leaf, - one gripping lever which comprises a gripping element, the gripping lever being movably mounted in rotation relative to the chassis about a first axis of rotation, between at least one rest position in which the gripping element is flush with an outer face of the door leaf, one active position in which the gripping element protrudes relative to the outer face of the door leaf and one open position in which the gripping lever unlocks the door leaf, - one transmission lever which delimits a first blocking face and a second blocking face, and which is pivotally mounted relative to the chassis about a second axis of rotation perpendicular to the first axis of rotation of the gripping lever, between a rest position and an actuating position in which the transmission lever actuates the opening of a lock of the door leaf, the transmission lever being driven in rotation by the gripping lever, and - a first reversible inertial safety system which is mounted on the chassis and which includes a first rocker beam carrying a first inertia mass, first rocker beam which includes a first blocking finger and which is pivotally mounted about a third pivot axis substantially perpendicular to the second axis of rotation of the transmission lever, between a rest position and a blocking position in which the first blocking finger prevents the rotation of the transmission lever, in case of shock, - a second irreversible inertial safety system which is mounted on the chassis and which includes a second rocker beam carrying a second inertia mass, second rocker beam which includes a second blocking finger and which is pivotally mounted about a fourth pivot axis substantially parallel to the third pivot axis of the first rocker beam, between a rest position and a blocking position in which the second blocking finger prevents the rotation of the transmission lever, in case of shock.