Rights of third parties: in an agreement not concluded, the third party does not acquire any rights to it. However, if, in the case of a countervailable contract, the third party acquires rights to the cause in good faith and in return for value before the contract is rejected, it acquires better title. Effects on hedging transactions: if the contract is cancelled due to illegality of the object and counterparty, hedging operations also become illegal. But a questionable « contract » has no influence on the security transaction. The basis for the decision to contest a contract at the choice of one of the parties depends on factors such as coercion, misrepresentation, unlawful influence, etc. Since it is one of the parties of choice, the aggrieved party can decide whether or not to invalidate the contract. A contract which, if concluded, may be cancelled a posteriori (cf. contract not concluded). . .