Abstract: The magnetic marker strip is formed of a signal strip made from ferromagnetic material with a low coercive force onto which there is applied ferromagnetic material whose coercive force is distinctly higher than that of the material of the signal strip. The signal strip is relatively long as compared with its width, and emits harmonic-containing signals in a first, unmagnetized state as a consequence of the magnetic field in the interrogation region and emits no harmonic-containing signal in a second state in this magnetic field. The ferromagnetic material with the larger coercive force is arranged in the form of a plurality of control elements at a spacing from one another on the signal strip, the width of the control elements being essentially equal to the width of the signal strip, and the control elements switching the signal strip into the first state when they are in a first, unmagnetized state, and switching the signal strip into the second state when they are in a second, magnetized state.