[2] In a case where a lessor seeks damages due to a lessee’s nonperformance of the duty to return the leased object on the ground that the lease termination and the lessee’s damage occurred, whether the lessee is liable for damages arising from the lessor’s nonperformance of the duty to return the leased object unless the lessee proves that the nonperformance was due to a cause not attributable to himself/herself (affirmative)

[3] In a case where: (a) the lessor Gap and the lessee Eul concluded a lease agreement for the equipment; and (b) the equipment to be returned was damaged; and (c) Eul sought damages from the nonperformance of the obligation to return the equipment against Eul on the ground that the equipment to be returned was damaged, the case holding that the lower court erred by misapprehending the legal doctrine, on the ground that: (a) there was a burden of proving that the equipment was damaged due to the negligence in the course of the use of the equipment; and (b) the lessor Gap bears the duty to repair the equipment; and (c) there was a burden of proving that the equipment was damaged due to the negligence in the area controlled and managed by Eul; and (d) the lessor Gap bears the duty to repair the equipment due to the malfunction of the equipment to be returned to Eul

[2] A lessee is obligated to preserve the leased object with the care of a good manager and restore the leased object to its original condition upon the termination of the lease (see Articles 374, 654, and 615 of the Civil Act). If the obligor fails to perform his/her obligation according to the content of the obligation, the obligee may claim damages, and if the obligor proves that he/she was unable to perform his/her obligation without any intention or negligence, the obligee is not liable (see Article 390 of the Civil Act).

Where a lessor seeks damages due to a lessee’s nonperformance of a duty to return an object on the ground that the leased object has been damaged upon the termination of a lease, the lessee is liable for damages incurred due to the lessee’s nonperformance of a duty to return the object unless the lessee proves that the nonperformance was caused by a cause not attributable to himself/herself, and the specific cause of the damage has not been revealed. Provided, That the same shall also apply to cases where the lessee is liable for damages incurred due to a defect existing in the area controlled and managed by the lessor, barring special circumstances, such as that the repair and removal of the defect belongs to the lessor’s duty to maintain the state necessary for the use and profit-making of the leased object, and that the lessee was aware or could have known of the defect in advance. This legal doctrine equally applies to the lessor’s liability for damages arising from the nonperformance of a duty to return the leased object due to damage.

[3] In a case where: (a) the lessor A and the lessee B concluded a lease agreement on the equipment; and (b) the equipment to be returned was damaged; and (c) Party B sought damages from the nonperformance of the obligation to return the equipment against Party B, the case holding that Party B is liable for damages arising from the nonperformance of the obligation to return the equipment, and barring special circumstances, Party B cannot be liable for damages arising from the nonperformance of the obligation to compensate for damages arising from the nonperformance of the obligation to return the equipment, unless it proves that the failure of the equipment was caused by a cause not attributable to Party B; (b) provided that Party B bears the duty to compensate for damages arising from the nonperformance of the obligation to return the equipment due to a defect in the area controlled and managed by Party B; and (c) the same applies to Party B’s failure to repair the equipment; (d) even if Party B bears the obligation to compensate for damages arising from the nonperformance of the obligation to compensate for the equipment due to a defect in the area controlled and managed by Party B, the lessor B bears the burden of proving the defect in the equipment’s equipment.

1. Part on the claim for return of unjust enrichment

Article 741 of the Civil Act provides, “A person who gains a benefit from another’s property or labor without any legal cause and thereby causes loss to the other person shall return such benefit.” Although the lessee continued to possess the leased object even after the termination of the lease agreement, in cases where the lessee does not have any profit because he/she did not use or make a profit from the leased object according to the original purpose of the lease agreement, the lessee’s return of unjust enrichment is not established even if the loss incurred to the lessor.

The lower court determined that the Defendant continued to possess the instant equipment subject to the lease even after the termination of the instant contract, but did not use or benefit from the instant equipment according to its original purpose due to the breakdown of the instant equipment, and thus, the Defendant did not constitute a return of unjust enrichment.

Examining the reasoning of the lower judgment in light of the aforementioned legal doctrine and the evidence duly admitted, the lower court’s determination is justifiable. In so determining, the lower court did not err by misapprehending the legal doctrine on return of unjust enrichment, or by violating

2. Part on the claim for repair expenses

A. The lower court dismissed the Plaintiff’s claim for repair cost, and the reasons are as follows.

If the breakdown of the instant equipment is not repaired, it shall be deemed that the Plaintiff, a lessor, bears the duty to repair the instant equipment, to the extent that the Defendant would be prevented from using and gaining profit from the instant equipment according to the purpose stipulated in the instant contract. As alleged by the Plaintiff, there is no evidence to prove that the failure occurred during the Defendant’s use of the instant equipment, or that the Plaintiff and the Defendant agreed to bear the repair cost of the instant equipment

B. However, the lower court’s determination is difficult to accept. The reasons are as follows.

(1) A lessee is obligated to preserve the leased object with the care of a good manager and restore the leased object to its original condition upon the termination of the lease (see Articles 374, 654, and 615 of the Civil Act). If the obligor fails to perform his/her obligation in accordance with the content of the obligation, the obligee may claim damages. However, if the obligor proves that he/she was unable to perform his/her obligation without intention or negligence, the obligee is not liable (see Article 390 of the Civil Act).

Where a lessor seeks damages due to a lessee’s nonperformance of a duty to return an object on the ground that the leased object was damaged upon the lessee’s termination of a lease, the lessee is liable for damages incurred due to the lessee’s nonperformance of a duty to return the object unless the lessee proves that the nonperformance was caused by a cause not attributable to himself/herself, and the specific cause of the damage is revealed. Provided, That if the damage incurred during the lease agreement is presumed to have occurred due to a defect existing in the area controlled and managed by the lessor, the repair and removal of the defect belongs to the lessor’s duty to maintain the state necessary for the use and profit-making of the leased object, and the lessee was aware or could have known of the defect in advance, barring special circumstances, the lessor cannot be held liable for damages arising from the lessor’s nonperformance of the duty to return the object due to the damage (see, e.g., Supreme Court en banc Decision 2012Da86895, 86901, May 18, 2017). This legal doctrine applies even if the lessor bears the duty to repair the damaged object (see Supreme Court Decision 29Da.

(2) The Plaintiff’s claim for repair cost terminated the lease of the instant equipment between the Plaintiff, the lessor, and the Defendant, who is the lessee. It constitutes a case where the Defendant seeks compensation for damages arising from the Defendant’s nonperformance of the duty to return the object on the ground that the instant equipment to be returned was damaged due to the

If the Defendant fails to prove that the failure in the instant equipment occurred due to a cause not attributable to himself/herself, he/she shall be liable for damages arising from the nonperformance of the duty to return an object. However, if the failure in the instant equipment that occurred during the lease agreement is presumed to have occurred due to a defect existing in the area controlled and managed by the Plaintiff, barring special circumstances, the Plaintiff cannot be liable for damages arising from the failure in the duty to return an object due to the failure in the instant equipment to the Defendant, barring special circumstances. The same applies to cases where the Plaintiff

(3) The lower court should have specifically deliberated and determined whether the failure in the instant equipment occurred due to a cause not attributable to the Defendant, or the failure in the instant equipment occurred due to a defect existing in the area controlled and managed by the Plaintiff.

Nevertheless, the lower court rejected the Plaintiff’s claim for repairing costs solely on the ground that the Plaintiff, a lessor, bears the burden of proving that the instant equipment was broken out due to negligence in the Defendant’s use, and that the Plaintiff is liable for repairing the instant equipment.

In so determining, the court below erred by misapprehending the legal principles as to the duty to compensate for damages and the burden of proof arising from the lessee’s nonperformance of the duty to return the leased object, where the leased object is damaged upon the termination of the lease. The ground of appeal assigning

3. Conclusion

Of the part against the Plaintiff, the part of the lower judgment against the Plaintiff’s claim for repair costs is reversed, and that part of the case is remanded to the lower court for further proceedings consistent with this Opinion. The remainder of the appeal is dismissed. It is so decided as per Disposition

Justices Lee Dong-won (Presiding Justice)