Gripper for grasping a hollow body, which comprises: - a gripper body; - a pair of jaws mounted in an articulated manner with respect to the gripper body about respective parallel axes (A1, A2) of rotation, between a releasing position, in which the jaws are spaced apart from one another to receive or release a hollow body, and a grasping position, in which the jaws have been moved towards one another and define a housing for the hollow body in order to clamp the latter; - a magnetic return device comprising at least one pair of magnetically opposed magnets (18, 19) that are able to urge the jaws towards their releasing position or, conversely, towards their grasping position; - wherein the magnetic return device comprises at least one fixed magnet secured to the gripper body, having a magnetic axis parallel to the axis (A1, A2) of rotation of the jaws, and at least one movable magnet coupled to at least one of the jaws, having a magnetic axis parallel to the axis (A1, A2) of rotation of the jaws; - and wherein each movable magnet is movable with respect to the gripper body between a first end position, in which the movable magnet is off-centre with respect to the fixed magnet and urges at least one of the jaws towards its releasing position, and a second end position, in which the movable magnet is off-centre with respect to the fixed magnet in an opposite direction to the first end position and urges at least this jaw towards its grasping position, characterized in that it comprises: - an actuator bearing the movable magnet, this actuator being movable in translation with respect to the gripper body between an extended position, corresponding to the releasing position of the jaws, in which a front end of the actuator projects into the housing, and a retracted position, corresponding to the grasping position of the jaws, in which the actuator is set back from the housing; - a pair of link rods coupling each of the jaws to the actuator. - a gripper body; - a pair of jaws mounted in an articulated manner with respect to the gripper body about respective parallel axes (A1, A2) of rotation, between a releasing position, in which the jaws are spaced apart from one another to receive or release a hollow body, and a grasping position, in which the jaws have been moved towards one another and define a housing for the hollow body in order to clamp the latter; - a magnetic return device comprising at least one pair of magnetically opposed magnets (18, 19) that are able to urge the jaws towards their releasing position or, conversely, towards their grasping position; - wherein the magnetic return device comprises at least one fixed magnet secured to the gripper body, having a magnetic axis parallel to the axis (A1, A2) of rotation of the jaws, and at least one movable magnet coupled to at least one of the jaws, having a magnetic axis parallel to the axis (A1, A2) of rotation of the jaws; - and wherein each movable magnet is movable with respect to the gripper body between a first end position, in which the movable magnet is off-centre with respect to the fixed magnet and urges at least one of the jaws towards its releasing position, and a second end position, in which the movable magnet is off-centre with respect to the fixed magnet in an opposite direction to the first end position and urges at least this jaw towards its grasping position, characterized in that it comprises: - an actuator bearing the movable magnet, this actuator being movable in translation with respect to the gripper body between an extended position, corresponding to the releasing position of the jaws, in which a front end of the actuator projects into the housing, and a retracted position, corresponding to the grasping position of the jaws, in which the actuator is set back from the housing; - a pair of link rods coupling each of the jaws to the actuator.