42 Not allowing people to rely on their own unlawful, dishonest or unreasonable conduct

There are several examples of this aspect of justice in the DCFR provisions on contract law. A recurring and important idea is that parties are expected to act in accordance with good faith and fair dealing. For example, a party engaged in negotiations has a duty to negotiate in accordance with good faith and fair dealing and is liable for loss caused by a breach of the duty.1. For later stages in the relationship it is provided that:

A breach of this duty does not in itself give rise to a liability to pay damages but may prevent a party from exercising or relying on a right, remedy or defence. The Principes directeurs say that ‘Each party is bound to act in conformity with the requirements of good faith and fair dealing, from the negotiation of the contract until all of its provisions have been given effect’.3. They also have an additional provision on performance: ‘Every contract must be performed in good faith. The parties may avail themselves of the contractual rights and terms only in accordance with the objective that justified their inclusion in the contract.’4. Taken together, these provisions are slightly wider than those of the DCFR but whether there would be much difference in practical effect may be doubted.

There are many specific provisions in the DCFR which can be regarded as concretisations of the idea that people should not be allowed to rely on their own unlawful, dishonest or unreasonable conduct. An example is the rule that the debtor is not liable for loss suffered by the creditor to the extent that the creditor could have reduced the loss by taking reasonable steps.5. Another recurring example is in the requirements to give reasonable notice before certain steps are taken which would be harmful to the other party's interest. And there are several rules which allow a person to rely on an apparent situation only if that person is in good faith.6. The rules on voidable contracts, even if their primary purpose is to ensure that a party can escape from a contract concluded in the absence of genuine freedom to contract, often have the incidental effect of preventing the other party from gaining an advantage from conduct such as fraud,7. coercion or threats.8.