In the event that the costs of a patient’s stay, consultations or procedures cannot be covered either by a health insurance organisation, or by the Minister for Veterans and Victims of War or by any other public body, the persons concerned or, failing this, their debtors or the persons designated by articles 205, 206, 207 and 212 of the Civil Code shall sign an undertaking to pay the costs of all kinds relating to the chosen scheme. They are obliged, except in emergencies, to pay a renewable advance on the patient’s admission to the establishment, calculated on the basis of the estimated length of the stay, the costs of consultations and procedures, or a provisional average rate for the stay approved by the ministers responsible for health and social security. Subject to the provisions of article L. 253-2 of the Code de l’Action Sociale et des Familles (French Code on Social Action and Families), where the advance paid exceeds the amounts due, the difference is returned to the person who paid it.