The invention relates to a method for detecting an identification object in an area (ZO) around an antenna device. The invention is characterized in that it comprises the following steps in which: a calibration signal (S_CAL) is emitted in the direction of the antenna device in order to determine a control power (PR); a functional signal (S_FONC) corresponding to the control power (PR) is emitted in the direction of the antenna device, such that the antenna device emits a predetermined magnetic field; the magnetic field (Br) received by the identification object, corresponding to the emitted magnetic field, is measured and compared with a nominal magnetic field (B0); and, depending on the result of said comparison, it is determined if the identification object is located inside the area (ZO) around the antenna device. The invention is suitable for motor vehicles.