국제물품매매협약상 계약해제의 효과

The avoidance of contract under CISG transforms the original contractual relationship into a winding-up or restitutionary relationship. When the contract is avoided, both parties are released from their primary performance obligations,while provisions in the contract that govern the rights and obligations of the parties after avoidance survive the avoidance. Under the winding-up relationship, the buyer has to return to the seller the very goods supplied by the seller; the seller has to return the price to the buyer in the currency of payment, whether this is different from the currency of account or not. If both parties are bound to make restitution, it has to be done concurrently. If only one party has performed, then restitution takes place unilaterally. These retitutionary obligations on avoidance are contractual and are not based on the unjust enrichment rules of any applicable domestic law. The place of restitution is to be determined by the general principles on which the CISG is based. The general principles can be found in the CISG provisions governing the place of delivery (Article 31) and the place of payment (Article 57)under the original contract. Thus, if, at the time of the avoidance of the contract the parties knew that the goods were at a particular place, the buyer have to return the goods at that place (Article 31(b)), and, in other cases, at the place where the buyer had his place of business (Article 31(c). The seller have to return the price to the buyer at the buyer’s place of business Article 57(1)(a). The costs of restitution should be borne by the unexempted non-performing party. For instance, the cost of carriage for shipping the goods back to the seller should be borne by the unexempted buyer if the seller avoided the contract, but by the unexempted seller if the buyer avoided the contract. As to the time of restitution,the unilateral restitution by the seller or buyer, as a general principle under Article 7(2), has to take place within a reasonable time upon or after avoidance of the contract. Upon avoidance, by way of concomitant equalization of benefits, the seller refunding the price to the buyer has to also pay interest on it from the date on which the price was paid, while the buyer has to account to the seller for all benefits which he has derived from the goods. As the seller’s duty to pay interest is based on the theoretical possibility to use the money, it is the interest rate at the seller’s place of business that should be applied. However the buyer’s duty to account for benefits is based on actual and net benefits, while the buyer’s own use of goods also constitutes a benefit which has to be restituted. When the goods cannot be returned in a substantially unimpaired condition, the buyer has to restitute by means of a surrogate, which includes the commodum ex re and the commodum ex negotiatione.