A turbomachine assembly for an aircraft comprising a nacelle with a nacelle structure, cowls attached to the structure to create an aerodynamic surface, an articulated cowl, comprising four edges, in the upper portion of the nacelle, an articulation at a first edge of the articulated cowl attached between the articulated cowl and the nacelle structure allowing the articulated cowl to move between a closed and an open position, a locking system at a second edge of the articulated cowl, opposite the first edge. The locking system comprises a handle actuable from the exterior of the nacelle, between a first position and a second position, a locking device movable between a locking position and an unlocking position, and a transmission system that moves the locking device from the locking position to the unlocking position when the handle passes from the first position to the second position, and vice versa.