Definition
A term drawn from French civil law denoting a contract — that is, a legally binding agreement between two or more parties giving rise to mutual obligations enforceable at law. The term appears in English-language legal sources primarily as a term of art when discussing French law, Louisiana law, or civil law systems derived from the Napoleonic Code. It is not a term of English common law and carries no independent legal force in common law jurisdictions.
Recognized Forms
/SUBTYPES
French civil law recognized several formally distinguished varieties of the contrat, each with distinct legal consequences:
1. BILATÉRAL (synallagmatique): A contract in which each party is bound to the other. Both sides assume obligations; the agreement is mutually enforceable. This corresponds roughly to the common law bilateral contract.
2. UNILATÉRAL: A contract in which only one side is bound. One party assumes an obligation while the other does not. This does not require the common law concept of consideration in the same way, as French law grounds enforceability differently.
3. COMMUTATIF: A contract in which each party's performance is regarded as the equivalent of the other's — a fair exchange of values determined at the time of contracting. Risk and value are treated as certain and knowable.
4. ALÉATOIRE: A contract in which the consideration or performance of one party depends on an uncertain event — that is, an aleatory contract. The value exchanged is contingent rather than fixed. Insurance contracts and annuities are classical examples.
Why It Matters in Research
Researchers encounter contrat most often in three contexts: (1) historical sources discussing French or civil law doctrine; (2) Louisiana legal materials, where the civil law tradition is operative and French-derived terminology persists in older cases, codes, and treatises; and (3) comparative law scholarship.
The critical navigational point is that the taxonomy of contrats in French civil law does not map cleanly onto common law contract categories. The bilatéral/unilatéral distinction in French law turns on whether one or both parties are bound by obligations — not on whether a promise was made in exchange for a promise or an act, as in common law. Researchers applying common law frameworks to sources using contrat terminology risk misreading the doctrinal significance of these distinctions.
Louisiana is the primary domestic jurisdiction where this matters practically. Pre-codification Louisiana cases and early Louisiana Civil Code provisions use contrat and its subtypes in ways that reflect French and Spanish civil law heritage, not common law doctrine. When researching Louisiana contract law in historical sources, treat contrat as a civil law term of art requiring civil law analysis.
Researchers consulting older English legal dictionaries should also be alert to the fragmented nature of the historical entries — as the source material here demonstrates, definitions were sometimes cut off mid-sentence, reflecting the compression common in 19th-century legal reference works. The full taxonomy of contrat varieties was occasionally truncated, leaving the aléatoire and other subtypes without complete definitions in some editions.
Historical Dictionary Support
Black's Law Dictionary (both the 1st and 2nd editions) and Rapalje & Lawrence are in substantial agreement on the core taxonomy of contrat varieties. All three sources enumerate the bilateral (synallagmatique), unilateral, commutatif, and aléatoire forms, treating this fourfold classification as the organizing framework inherited from French civil law. The 2nd edition of Black's is the most complete of the available sources, carrying the aléatoire definition further than the 1st edition entry, which appears to have been cut mid-definition in the surviving text.
Rapalje & Lawrence adds a useful gloss on the commutatif form, noting that it involves something "supposed to be an equivalent" — language that highlights the civil law's concern with commutative justice and proportionality in exchange, a concept with deeper philosophical roots than the common law's relatively agnostic stance toward adequacy of consideration.
None of these historical sources address the procedural or remedial consequences of the distinctions they enumerate, which limits their utility for researchers trying to understand how French courts applied the taxonomy in practice. For that, recourse to French civil law treatises or the Code Civil itself is necessary.
Jurisdictional Note
Contrat as a legal term is operative in Louisiana, where the civil law tradition shapes contract doctrine. It also appears in Quebec law materials, international commercial arbitration contexts involving French-law-governed contracts, and comparative law scholarship. In all other American jurisdictions, it functions purely as a descriptive or historical term without independent legal effect.