Deals & Cases
Lawsuit for Return of Unjust Enrichment | Prevailed with "Dismissal of the Plaintiff's Claim" in a Lease Down Payment Return Lawsuit
The client, who had lost at first instance in a lawsuit for return of unjust enrichment, visited this law firm to seek more specialized legal advice on appeal.
1. Lawsuit for Return of Unjust Enrichment | The Client Who Requested an Appellate Response
The client who inquired about a lawsuit for return of unjust enrichment was in a legal dispute concerning the return of a lease down payment.
Having lost at first instance after preparing alone, the client requested legal assistance for the appeal and received a consultation with an attorney.
The client had entered into an annual rent lease agreement to lease certain buildings, including a pension, and received a down payment of 22 million won.
The agreement was made orally, and there was no separate recording or written contract.
However, the other party unilaterally gave notice of cancellation of the agreement a few days before the balance payment date, demanded the return of half of the down payment, and filed a lawsuit for return of unjust enrichment.

Meaning and Procedure of a Lawsuit for Return of Unjust Enrichment
A claim for return of unjust enrichment refers to a lawsuit seeking the return of a benefit that another person has unjustly obtained.
Where a benefit has been obtained without a legitimate legal cause, it need not necessarily be unlawful, and a lawsuit is possible as long as the unjust manner can be specifically proved.
In this return lawsuit, the key issues were whether the agreement was validly formed and who was responsible for the cancellation of the agreement.
The procedure for a lawsuit for return of unjust enrichment is as follows.
Procedure | Description |
Preliminary review | The requirements for establishing unjust enrichment (a benefit without legal cause, the occurrence of loss, and causation, among others) are reviewed and the evidence is organized. |
Filing of the complaint | A complaint seeking the return of unjust enrichment is filed with the court of competent jurisdiction, and the lawsuit commences. |
Submission of the answer | The defendant submits an answer containing the rebuttal arguments to the plaintiff's claim. |
Pleading and proof | Both sides repeatedly assert and prove their positions, contesting the contractual relationship, attributability, and the nature of the benefit, among others. |
Examination of evidence | The court reviews the submitted evidence, such as documents, call records, the contract, and account records. |
Conclusion of pleadings | When it is determined that there are no further issues to contest, the pleadings are concluded. |
Conclusion by the court | The court determines whether unjust enrichment is to be returned and the scope of the return, and renders its judgment. |
2. Lawsuit for Return of Unjust Enrichment | The Attorney's Pleading Strategy
At first instance, the court found that 10 million won, corresponding to 10% of the annual rent of 120 million won, was a down payment having the character of cancellation money, and that the remaining 12 million won was an advance payment of the annual rent.
Whereas cancellation money is borne as a disadvantage by the party who voluntarily cancels the agreement, an advance payment is money paid in advance on the premise of performance of the agreement, and it therefore becomes subject to return if the agreement is canceled.
Accordingly, the court ruled that the 12 million won the client had received as an advance payment should be deemed unjust enrichment and returned.
The attorney who reviewed the client's case set the direction of the pleadings on appeal so as to clarify that the essence of the lawsuit for return of unjust enrichment lay in the attribution of responsibility for the breakdown of the agreement and the resulting character of the down payment.
Argument That the Other Party's Evidence Was Weak
The other party argued for cancellation of the agreement on the grounds of fraud or mistake, asserting that they had not been informed that part of the building was unauthorized and that it was registered as a rural fishing village homestay business, and that they had therefore been unable to operate a pension business.
The attorney who undertook the pleadings emphasized that there was insufficient objective evidence to prove this in the lawsuit for return of unjust enrichment.
The court likewise determined that it was difficult to recognize deception or a mistake as to an important part based on the other party's assertion alone.
Securing Evidence Through the Contents of the Call Between the Other Party and the Client
Decisively, the attorney secured and submitted as evidence the contents of the call between the parties made immediately after the abandonment of the agreement.
The contents of the call showed that, when the client asked the reason for abandoning the agreement, the other party answered that they were abandoning it not because of the unauthorized-structure issue or any ground making the business impossible, but because of the burden of additional investment costs.
The contents of the call submitted by the attorney served as important circumstantial evidence in the lawsuit for return of unjust enrichment, contradicting the other party's earlier assertions.
3. Lawsuit for Return of Unjust Enrichment | Trial Result: "Dismissal of the Plaintiff's Claim"
The other party argued that part of the down payment constituted an advance payment and should therefore be returned, but the appellate court did not accept this.
Where a down payment is recognized as an advance payment, the portion not performed upon cancellation of the agreement becomes subject to return, but the attribution of the down payment is determined according to who is responsible for the cancellation of the agreement.
The court found that, in this case, responsibility for the cancellation of the agreement lay with the plaintiff, and it therefore dismissed the plaintiff's claim in the lawsuit for return of unjust enrichment in its entirety.
As a result, the court rendered a judgment dismissing the plaintiff's claim, and the case concluded with the client prevailing.
4. Lawsuit for Return of Unjust Enrichment | In a Situation Requiring a Lawsuit
In a lawsuit for return of unjust enrichment, the review of the facts and the law is very important, regardless of whether the form of the agreement is oral or written.
If you are considering an appeal in light of the first-instance result, you must closely analyze the basis for the preceding judgment together with a specialist and review it strategically in order to expect a favorable result on appeal.
Drawing on extensive experience in various civil lawsuits, Daeryun Law Firm provides a systematic response strategy throughout the entire course of litigation.
If you are involved in a down payment return dispute such as this case, please secure the assistance of a specialist and protect your rights through a 🔗legal consultation reservation.
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This content is based on actual cases handled by Daeryun Law LLC and has been partially adapted. All copyrights belong to Daeryun Law LLC.
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