(EN) The invention relates to a method for enrolling a holder of a biometric transaction device (3), including the following steps: - storing at least one biometric pattern (N1-N7) in the device, the method being characterised in that it comprises the following steps: a) providing the holder with a portable, mobile power connector (2), configured to trigger said storing; - b) and/or activating (E10, E10bis, A1) the biometric pattern (N1-N7), said activation being carried out in response to or in association with a successful authentication (6, 6bis, 9) of the holder. The invention likewise relates to the corresponding system (1A, 1B).