Abstract: A positioning aid for a magnetic device used for positioning a shuttering means, the magnetic device being movable between a position of use, in which said magnetic device is in contact with a ferromagnetic shuttering support, and a position of non-use, in which said magnetic device is spaced apart from the shuttering support, said positioning aid comprising at least one retaining device relative to which the magnetic device is supported against a holding force of said magnetic device, and further comprising at least one elastic support unit for producing a lifting force against said holding force so as to hold the magnetic device in the position of non-use.