A method for identifying a user by means of a communication device, wherein an identification document is assigned to the user, the method comprising: detecting a biometric feature of the user by means of the communication device in order to obtain a detected biometric feature; transmitting the detected biometric feature to an electronic identification service via a communication network by the communication device; and comparing the detected biometric feature with a biometric reference feature by the electronic identification service to identify the user; and reading out the biometric reference feature from an electronic circuit of the identification document by means of the communication device in order to obtain a read out biometric reference feature; and transmitting the read biometric reference feature by the communication device via the communication network to the electronic identification service, wherein reading out the biometric reference feature from the electronic circuit of the identification document by means of the communication device further comprises reading out personal data in order to obtain read out personal data, and wherein the transmission of the read out biometric reference feature by the communication device via the communication network to the electronic identification service further comprises transmitting the read out personal data to the electronic identification service, wherein the personal data indicates the identity of the user, wherein the method further comprises the following steps: capturing data from a machine-readable zone of the identification document by means of an image camera of the communication device; and extracting an identification identifier of the identification document from the captured data, wherein the validity of the identification document is checked by means of the captured data, wherein a check of the certificate chain of an electronic signature associated with the identification document is carried out to check the validity of the identification document, wherein a reference certificate is pre-stored in a memory of the communication device for this purpose. detecting a biometric feature of the user by means of the communication device in order to obtain a detected biometric feature; transmitting the detected biometric feature to an electronic identification service via a communication network by the communication device; and comparing the detected biometric feature with a biometric reference feature by the electronic identification service to identify the user; and reading out the biometric reference feature from an electronic circuit of the identification document by means of the communication device in order to obtain a read out biometric reference feature; and transmitting the read biometric reference feature by the communication device via the communication network to the electronic identification service, wherein reading out the biometric reference feature from the electronic circuit of the identification document by means of the communication device further comprises reading out personal data in order to obtain read out personal data, and wherein the transmission of the read out biometric reference feature by the communication device via the communication network to the electronic identification service further comprises transmitting the read out personal data to the electronic identification service, wherein the personal data indicates the identity of the user, wherein the method further comprises the following steps: capturing data from a machine-readable zone of the identification document by means of an image camera of the communication device; and extracting an identification identifier of the identification document from the captured data, wherein the validity of the identification document is checked by means of the captured data, wherein a check of the certificate chain of an electronic signature associated with the identification document is carried out to check the validity of the identification document, wherein a reference certificate is pre-stored in a memory of the communication device for this purpose.