What is an IOU?
The acknowledgment of debt is an act under private signature which allows the person who does it to commit to another person to pay him a sum of money. It is most often used to take note of the existence of a debt between two people, professionals, parents, or private individuals.
Acknowledgment of valid debts
It is article 1376 of the civil code which provides for the conditions of validity of an acknowledgment of debts. The acknowledgment of debt is a document (it can be a simple white sheet) on which appear several pieces of information. The document must include the signature of the debtor (the one on whom the debt weighs) and the amount of the debt.
The signature must be made by the debtor's own hand, except in the case of an electronic signature. The amount of the debt must be written in figures and in words. If there is a difference between the two, the number written in letters will be taken into account.
proof of debt
What is called “acknowledgment of debt” does not create an obligation to repay a debt. Indeed, if no acknowledgment of debt has been signed by the debtor, in the event of a loan agreed orally or a poorly drafted acknowledgment of debt, the sum is still due. The acknowledgment of debt only facilitates the proof of the debt that exists independently of its recognition. So, plan an acknowledgment of debt if it is between you and an individual.
Example: IOU Template
Only the mentions specified above are necessary. However, there are templates available for drafting an acknowledgment of debt regardless of the qualities and relationship of debtors and creditors. There is one on https://www.service-public.fr/particuliers/vosdroits/R38209.