A. The meaning of "an error" under Article 743 of the Civil Act, and whether the payment is deemed to have waived the benefit of time when it was performed with the knowledge of the period of payment (affirmative)

B. The case holding that the lower court’s determination rejecting the assertion that the statutory interest equivalent to the interim retirement allowance received by an employee would constitute unjust enrichment where interim retirement is invalid, was somewhat wrong at the time of explaining its reasoning, but did not err in its conclusion as a repayment prior to

A. Article 743 of the Civil Code provides that "the due date of mistake" means that the due date has arrived because it is true that the former has not been known, and thus the person who repaid the due date knowingly shall be deemed to have waived the benefit of the due date.

B. The case holding that the lower court did not err in its conclusion on the ground that it was somewhat erroneous in rejecting the claim that the amount equivalent to the statutory interest on the interim retirement allowance received by the employee would constitute unjust enrichment, but it is difficult to regard the payment of the debt prior to the due date due date due to mistake as the repayment of the debt was made,

Article 743 of the Civil Act, Article 28 of the Labor Standards Act

[Plaintiff-Appellant] Lee Tae-tae et al., Counsel for plaintiff-appellant

Suwon Electronic Co., Ltd., Counsel for the defendant-appellant and one other

Seoul Civil District Court Decision 90Na5671 delivered on January 9, 1991

The appeal is dismissed.

The costs of appeal are assessed against the defendant.

(1) We examine the first ground for appeal.

According to the reasoning of the judgment of the court below, the plaintiff was employed by the non-party Electric Cable Co., Ltd. on March 17, 1969 and was employed as a technical employee on June 197 as well as the position of the non-party Nos. 5 and promoted to the non-party No. 4 on June 5, 1978. The non-party No. 5 transferred the business of the former Electric Cable Co., Ltd. to the defendant on February 5, 1983, while the non-party No. 5 transferred the business of the former Electric Co., Ltd. to the defendant on March 1, 1983 without receiving retirement allowances from the individual employees at the time of the transfer of the business, the court below determined that the plaintiff would receive retirement allowances from the above non-party No. 2 after adding the number of years of service from the date of entry to the date of retirement of the defendant Co. 1, Ltd. to the date of retirement of the previous company No. 98 years of retirement allowance by the plaintiff's decision.

(2) We examine the second ground for appeal.

According to the reasoning of the judgment of the court below, the court below rejected the defendant's assertion that the plaintiff received an interim retirement allowance without any cause, so the legal interest equivalent to the above amount should be deducted from the retirement allowance that the defendant should pay to the plaintiff as unjust enrichment, on the ground that the above interim retirement allowance was paid in advance by the defendant himself against the plaintiff's will, not only because the defendant paid part of the retirement allowance, but also that the defendant had caused the plaintiff to delay in the performance of the obligation to return unjust enrichment by claiming the return of the above interim retirement allowance.

However, according to the provisions of Article 743 of the Civil Act, when an obligor pays an interim retirement allowance to the obligee due to mistake, the obligee shall return the benefit accrued therefrom. Thus, even though the court below acknowledged that the Defendant paid an interim retirement allowance to the Plaintiff prior to the due date, it does not have any error in the Defendant’s rejection of the claim for return of unjust enrichment, and has the Plaintiff’s claim for return of unjust enrichment. However, the court below erred in holding that the Defendant is liable to pay damages for delay due to delay of the return of the interim retirement allowance in filing a claim for return of unjust enrichment equivalent to the statutory interest accrued before

However, it is difficult to view that the defendant paid an interim retirement allowance to the plaintiff and received it by mistake even if the defendant paid it to the plaintiff, and the person who paid it with the knowledge of the period of payment prior to the due date, would waive the benefit of the due date. As such, the court below's fact-finding, where the plaintiff selected the retirement allowance by adding up the number of years of service from the time when he was employed by the non-party Electric Cable at the time of the defendant company's retirement, and it cannot be recognized that the plaintiff received an interim retirement allowance by itself (it seems that the defendant paid an interim retirement allowance to the plaintiff against the plaintiff against the will of the non-party who did not reject the decision by the court below). This is because even if the defendant paid it to the plaintiff, it is difficult to view that the defendant paid the interim retirement allowance to the plaintiff before the due date of payment due to mistake, and even if it is not known that the above interim retirement treatment as a large enterprise as above does not have any effect as a retirement before the due date of payment due to the defendant's gross negligence as well as the defendant paid the retirement allowance.

Therefore, the defendant's argument that the defendant should deduct unjust enrichment equivalent to the legal interest accrued prior to the due date from the retirement allowance that the defendant should pay to the plaintiff in this case where the above interim retirement allowance payment by mistake is not observed, should be rejected. Therefore, the judgment of the court below is somewhat erroneous in its reasoning, but it does not err in the conclusion of rejecting it, and it does not affect the conclusion of the judgment. The argument is groundless.

(3) Therefore, the appeal is dismissed and all costs of appeal are assessed against the losing party. It is so decided as per Disposition by the assent of all participating Justices on the bench.

Justices Lee Jae-sung (Presiding Justice)