Tool for uncoupling a connection assembly, the connection assembly comprising: - a first connector, in particular a multi-contact connector comprising hooking reliefs, and - a second connector, in particular a multi-contact connector, of a type that complements the first connector, the second connector forming a receptacle designed to be fastened to a panel, the first and second connectors each comprising a housing (80, 90) extending along an axis and comprising a connection face, the first and second connectors being connected together via their connection faces, the tool comprising: - at least one hook comprising at least one hooking relief (52, 53) designed to interact by hooking to a hooking relief (86, 87) of the first housing, - a hydraulic circuit comprising at least one cylinder, at least one piston called main piston forming, together with the cylinder, a master cylinder, at least one conduit (61, 62) connecting the main piston to at least one secondary piston, the tool being characterized in that: - the hook further comprises a locking tip; - the hydraulic circuit may be actuated once the hooking of at least one relief of the first housing via the hooking relief of the hook has been achieved, thereby giving rise to the movement of the main piston that transmits the pressure of the hydraulic fluid toward the at least one secondary piston that shifts from its inactive position, in which it is locked by the locking tip until the hooking of the relief of the first housing has been achieved, to an active position, in which it is unlocked and is able thus to exert a thrust force against the panel to which the receptacle is fastened, in such a manner as to achieve the uncoupling/disconnection between the receptacle and the first connector. - a first connector, in particular a multi-contact connector comprising hooking reliefs, and - a second connector, in particular a multi-contact connector, of a type that complements the first connector, the second connector forming a receptacle designed to be fastened to a panel, the first and second connectors each comprising a housing (80, 90) extending along an axis and comprising a connection face, the first and second connectors being connected together via their connection faces, - at least one hook comprising at least one hooking relief (52, 53) designed to interact by hooking to a hooking relief (86, 87) of the first housing, - a hydraulic circuit comprising at least one cylinder, at least one piston called main piston forming, together with the cylinder, a master cylinder, at least one conduit (61, 62) connecting the main piston to at least one secondary piston, - the hook further comprises a locking tip; - the hydraulic circuit may be actuated once the hooking of at least one relief of the first housing via the hooking relief of the hook has been achieved, thereby giving rise to the movement of the main piston that transmits the pressure of the hydraulic fluid toward the at least one secondary piston that shifts from its inactive position, in which it is locked by the locking tip until the hooking of the relief of the first housing has been achieved, to an active position, in which it is unlocked and is able thus to exert a thrust force against the panel to which the receptacle is fastened, in such a manner as to achieve the uncoupling/disconnection between the receptacle and the first connector.