A method for biometric-based triggering of a useful action by means of an ID token associated with a user, which ID token has been personalised by a personalisation-related sensing and storing of a biometric feature and has been activated by an activation-related sensing of a corresponding feature, the method comprising the steps of: a) presenting the activated ID token to a device for triggering a useful action; b) sensing the corresponding biometric feature of the user in relation to the useful action; c) comparing the corresponding biometric feature of the user sensed in relation to the useful action with the corresponding biometric feature of the user stored in relation to personalisation; and d) if the comparison indicates that the corresponding biometric feature of the user sensed in relation to the useful action adequately matches the corresponding biometric feature of the user stored in relation to personalisation: triggering the useful action, the personalisation-related sensing of the biometric feature comprising the steps of: 1) personalising a non-personalised ID token using at least one identity-establishing attribute of the user; 2) writing the identity-establishing attribute in a first persistent memory area of the ID token, the first persistent memory area being a protected memory area; 3) detecting the biometric feature of the user; 4) writing the biometric feature of the user in a second persistent memory area of the ID token, the second persistent memory area being a protected memory area, in order to thus obtain a stored biometric feature of the user; wherein a protected memory area is protected by program instructions stored in the ID token in such a way that a reading and/or writing in the protected memory are is possible only if the program instructions conclude that a predetermined condition is satisfied for the reading and/or writing, wherein the writing of the identity-establishing attribute and of the biometric feature of the user during the personalisation-related sensing may be performed only on a personalisation configuration intended for this purpose, wherein a certificate is received from a trust entity and contains at least the identity-establishing attribute in addition to an identifier. a) presenting the activated ID token to a device for triggering a useful action; b) sensing the corresponding biometric feature of the user in relation to the useful action; c) comparing the corresponding biometric feature of the user sensed in relation to the useful action with the corresponding biometric feature of the user stored in relation to personalisation; and d) if the comparison indicates that the corresponding biometric feature of the user sensed in relation to the useful action adequately matches the corresponding biometric feature of the user stored in relation to personalisation: triggering the useful action, the personalisation-related sensing of the biometric feature comprising the steps of: 1) personalising a non-personalised ID token using at least one identity-establishing attribute of the user; 2) writing the identity-establishing attribute in a first persistent memory area of the ID token, the first persistent memory area being a protected memory area; 3) detecting the biometric feature of the user; 4) writing the biometric feature of the user in a second persistent memory area of the ID token, the second persistent memory area being a protected memory area, 1) personalising a non-personalised ID token using at least one identity-establishing attribute of the user; 2) writing the identity-establishing attribute in a first persistent memory area of the ID token, the first persistent memory area being a protected memory area; 3) detecting the biometric feature of the user; 4) writing the biometric feature of the user in a second persistent memory area of the ID token, the second persistent memory area being a protected memory area,