The present invention relates to a method of privacy-preserving during an access to a restricted e-service requiring user private data from a smart card. The invention relates more particularly to the field of methods implemented so that the user has the guarantee that only the private data needed to access to the e-service are extracted from the smart card. It is to guarantee that the user has a perfect knowledge of his private data provided by his smart card to a requester. With the invention a message notifying to the user the very nature of the identity assertion is displayed on the screen of the smart card. By doing so, the card ensure 100% security with regard to user consent: the data read out of his card cannot differ comparing to the data requested by the service provider through the terminal.