An intermediate fitting for a closing system including a leaf pivotally mounted to a sash-frame, such an intermediate fitting: - including: - a striker, including an active portion, and intended to be made integral with the sash-frame or the leaf, respectively; - a hooking finger, intended to be made integral with the leaf or the sash-frame, respectively, and including, on the one hand, an active portion, on the other hand, a base intended to be made integral with the leaf or the sash-frame, respectively, yet on the other hand, a hooking organ including the active portion of this hooking finger and, also on the other hand, means for movably mounting the hooking organ relative to the base, between an extended position and a retracted position relative to the base; - restricting means for at least restricting, even impeding, the movement of the hooking organ relative to the striker and/or relative to the base; - wherein the active portion of the striker and the active portion of the hooking finger are designed to cooperate with each other, at least in the closed position of the leaf with respect to the sash-frame; - wherein the restricting means include a lever, on the one hand, which the hooking organ includes, on the other hand, which is movable relative to this hooking organ and, yet on the other hand, which cooperates with the striker or with the base, while the intermediate fitting is configured so that, on the one hand and in a closing phase of the leaf relative to the sash-frame, the active portion of the striker and the active portion of the hooking finger adopt an active position of cooperation, on the other hand and in a next closing phase, the lever of the restricting means moves from an inactive position of cooperation into an active position of cooperation and, yet on the other hand and during the opening of the leaf, the lever moves from the active position of cooperation into the inactive position of cooperation. - including: - a striker, including an active portion, and intended to be made integral with the sash-frame or the leaf, respectively; - a hooking finger, intended to be made integral with the leaf or the sash-frame, respectively, and including, on the one hand, an active portion, on the other hand, a base intended to be made integral with the leaf or the sash-frame, respectively, yet on the other hand, a hooking organ including the active portion of this hooking finger and, also on the other hand, means for movably mounting the hooking organ relative to the base, between an extended position and a retracted position relative to the base; - restricting means for at least restricting, even impeding, the movement of the hooking organ relative to the striker and/or relative to the base; - wherein the active portion of the striker and the active portion of the hooking finger are designed to cooperate with each other, at least in the closed position of the leaf with respect to the sash-frame; - wherein the restricting means include a lever, on the one hand, which the hooking organ includes, on the other hand, which is movable relative to this hooking organ and, yet on the other hand, which cooperates with the striker or with the base, while the intermediate fitting is configured so that, on the one hand and in a closing phase of the leaf relative to the sash-frame, the active portion of the striker and the active portion of the hooking finger adopt an active position of cooperation, on the other hand and in a next closing phase, the lever of the restricting means moves from an inactive position of cooperation into an active position of cooperation and, yet on the other hand and during the opening of the leaf, the lever moves from the active position of cooperation into the inactive position of cooperation. - a striker, including an active portion, and intended to be made integral with the sash-frame or the leaf, respectively; - a hooking finger, intended to be made integral with the leaf or the sash-frame, respectively, and including, on the one hand, an active portion, on the other hand, a base intended to be made integral with the leaf or the sash-frame, respectively, yet on the other hand, a hooking organ including the active portion of this hooking finger and, also on the other hand, means for movably mounting the hooking organ relative to the base, between an extended position and a retracted position relative to the base; - restricting means for at least restricting, even impeding, the movement of the hooking organ relative to the striker and/or relative to the base; - wherein the active portion of the striker and the active portion of the hooking finger are designed to cooperate with each other, at least in the closed position of the leaf with respect to the sash-frame; - wherein the restricting means include a lever, on the one hand, which the hooking organ includes, on the other hand, which is movable relative to this hooking organ and, yet on the other hand, which cooperates with the striker or with the base, while the intermediate fitting is configured so that, on the one hand and in a closing phase of the leaf relative to the sash-frame, the active portion of the striker and the active portion of the hooking finger adopt an active position of cooperation, on the other hand and in a next closing phase, the lever of the restricting means moves from an inactive position of cooperation into an active position of cooperation and, yet on the other hand and during the opening of the leaf, the lever moves from the active position of cooperation into the inactive position of cooperation.