Article 1326 of the Civil Code stipulates that "the legal act by which a sole party agrees with a second party to pay them a sum of money or deliver a fungible asset must be identified in a deed which includes the signature of that who undertook this agreement as well as the sum or quantity in figures or words written by themselves. If there is a difference, the private deed is the evidence of the sum written in words".
The acknowledgement of debt may also :