Bilateral contract

The bilateral contract or synallagmatic contract is a contract that generates reciprocal obligations for both contracting parties.

The term synallagmatic derives from the Greek synallagma (συνάλλαγμα) "contract, stipulation", which is composed of without (σύν) "together" and alagmo (ἀλλάσσω) "take or give in exchange, exchange". Add ico (ικός) "characteristic of, similar to, typical of" and we conclude that, due to its roots, synalagmatic means "what is characteristic of mutual exchange".

It is a type of contract that is opposed to the unilateral contract, in which only obligations arise for one of the parties (for example, the donation).

Examples

The most classic example is the sales contract in which:

• One party (the seller) is obliged to deliver a property, and the other (the buyer) to pay its price;
• One party (the buyer) is obliged to pay the price to another (the seller) that is for its part obliged to transfer the property of the thing, a situation proper to French law.

There are, however, a multitude of bilateral contracts, with reciprocal obligations, such as leases, exchanges, provision of services or many others.

In causal terms, the classical doctrine affirms that in the framework of a bilateral or synallagmatic contract, the cause of the obligation of a contracting party has as its object the obligation of the other, and reciprocally. This vision allows us to consider as null and void any agreement lacking cause, that is, not having legal justification. In this case, a judge may be forced to reclassify the contract in order to discover its true nature or could even decree the nullity of the contract.

In this type of contract, the exception of non-execution can be applied, through which one of the parties can refuse to fulfill its obligations covered by the counterparty's breach of its own obligations.

Classes

Perfect bilateral or synallagmatic contract

It is the one that generates reciprocal obligations for both contracting parties from its origin. For example, the sale, lease, exchange, transport.

Bilateral or imperfect synallagmatic contract

It is that contract that was originally created as a unilateral contract, but later became a bilateral one due to the generation of obligations to the creditor. For example, the mandate is a naturally unilateral contract, but if the agent must pay his money for unforeseen expenses in the order, the contract will become bilateral (imperfect, of course), because now the principal will have the obligation to reimburse said expenses to the leader.