The harpoon comprises a bistable actuator (34) having a rod (56) for actuating the finger (32) the rod being movable between a retracted resting position and an extended position of deployment of the finger (32).The bistable actuator (34) comprises a tappet (52) that is movable during a first impulse comprising a stroke (34) in a first direction and then a stroke in a second direction opposite to the first direction in order to cause the switch of the rod (56) from its retracted position to its extended position.The tappet (52) is movable during a second impulse comprising a stroke in the first direction and then a stroke in the second direction in order to cause the switch of the rod (56) from its extended position to its retracted position.The actuator (34) is configured so as to allow the return of the rod (56) to its retracted position when the tappet (52) moves along the first stroke in the first direction during the second impulse.