Consensus
Consensus is the parties’ mutual assent on the contract, assessed by their real intention or, failing that, justified reliance.
Consensus is required for a contract to come into existence in Swiss obligations law. It may be actual, where the parties truly share the same intention, or normative, where one party’s declaration must be understood according to good faith and reliance. Agreement must cover at least the essential terms of the transaction. Lack of consensus prevents contract formation, while defects in will such as error or fraud may make an existing contract challengeable. The distinction is important because formation and invalidity lead to different remedies and time limits.