Patrimony is a key concept in the French Civil Code, and this concept is shared in most systems that are based on French law (although it may have another name in other languages). Under this concept, anything that can be assigned a monetary value is part of the patrimony of one and only one natural person or artificial person. Conversely, all of a person's valuables form part of their patrimony. This includes things that under common law would be treated as separate property interests to which different persons may have some sort of interest, such as the right to use a person's name, their reputation, the integrity of their body against injury, as well as their real property and personal property. In other words, anything of value belongs exclusively to a single person, corporation or married couple, and different types of property are usually treated identically at law.

This concept makes certain legal concepts and remedies available at common law impossible in a Civil Code. For example:

- A Civil Code could not recognize the concept of a trust, that is property controlled by one person for the benefit of one or more beneficiaries. Modern Civil Codes now contain the concept of patrimony of affectation that operate similarly to a trust.

- Although Civil Codes recognize that a charge can be placed on real or personal property (a hypotec), the only remedy available to the lender is sale of the charged property. The remedies of foreclosure or repossession are not available under a Civil Code (i.e. the lender cannot take ownership of the property in satisfaction of the loan).