The “préjudice d’impréparation,” which can be translated as “prejudice resulting from the lack of preparation”, appeared very recently in French law. It aims to compensate the moral distress resulting from the shock suffered by the victim who learns that a hidden medical risk, for which he or she has therefore not been able to prepare, has occurred. It is a kind of presumption of damage binding the obligation of information to fundamental rights such as the protection and the dignity of the human being and the integrity of the human body. However, this distress damage raises many difficulties, such as its assessment or its articulation with other damages, like the loss of opportunity to avoid damages resulting from the medical act. This study tries to present this new damage in French law.