상사계약 무효로 인한 부당이득반환청구권의 소멸시효에 관한 고찰 - 판례 분석을 중심으로 -

In principle, the 5-year extinctive prescription applies to claims arising from commercial activities(Article 64 of Commercial Act). The precedent applies the extinctive prescription to bonds that are substantially identical as a modification of bonds arising from commercial activities. Commercial extinctive prescription applies to the right to claim damages due to non-performance of a commercial contract, and to the right to claim restoration due to revocation of a commercial contract. However, the position of precedents on the extinctive prescription of the right to claim for restitution of unjust enrichment upon the invalidity of commercial contract is inconsistent. In case of a claim for the restitution of unjust enrichment arising from the cancellation or invalidation of a commercial contract, the precedent applies the 5-year extinctive prescription if it is necessary to settle it quickly. In this paper, among the precedents which are adjudicated up to January 2022, cases involving the extinction prescription period of the right to claim for restitution of unjust enrichment due to the invalidity of the commercial contract are classified into 4 types such as (1) If it does not fall under commercial activity, (2) In case of requesting the restitution of unjust enrichment upon insurance money, (3) If the commercial contract is invalid, (4) when a merchant enters into a standardized contract with a large number of people. And each type was analyzed. The Supreme Court seems to take the 10-year extinctive prescription theory when requesting the restitution of infringement unjust enrichment, but in other cases, which request the restitution of benefit unjust enrichment upon invalidity of a commercial contract, it seems to take 5-year extinctive prescription theory. Occasionally, the Supreme Court has taken the theory of 10-year extinctive prescription in case of requesting the restitution of benefits. However, the right to claim the restitution of unjust enrichment upon the invalidation of commercial contracts is not much different from the right to claim restoration upon the revocation of commercial contracts in that it liquidates the legal relationship arising from the commercial activities. In other words, it is reasonable to apply the 5-year extinctive prescription, because the right to claim for restitution of unjust enrichment upon the invalidity of commercial contract is recognized the same as the original bonds arising from the commercial activities.