The plaintiff's claim is dismissed.

Litigation costs shall be borne by the plaintiff.

1. Basic facts

A. On May 2015, the Plaintiff entered into a design contract with the Defendant and Gangseo-gu Seoul Metropolitan Government D Ground Building (hereinafter “instant building”) with the construction cost of KRW 71,50,000 (including value-added tax). Around July 2015, the Plaintiff entered into a remodeling contract with the Defendant and the building of this case (hereinafter “instant construction”) with the construction cost of KRW 1,868,790,000 (including value-added tax) (hereinafter “instant contract”).

On October 15, 2015, the Plaintiff completed the instant construction work.

B. On February 4, 2016, the Plaintiff and the Defendant determined the remaining construction cost as KRW 561,290,000 among the construction cost to be paid by the Plaintiff to the Defendant as design contract price, removal construction cost, remodeling construction cost, additional construction cost, etc. However, KRW 400,000 shall be immediately paid as corporate bank loans, and KRW 161,290,000 shall be paid by March 31, 2016, and where the payment date is not made by the payment date, the Plaintiff and the Defendant agreed to additionally pay interest at a rate of 20% per annum for the unpaid amount from the following day to the date of full payment.

C. The Plaintiff paid KRW 1,920,000,000 to the account in the name of the Defendant or the account in the name of E operated by the Defendant from June 3, 2015 to February 5, 2016.

[Reasons for Recognition] Unsatisfy, entry of Gap evidence 1 to 5, the purport of the whole pleadings

2. Assertion and determination

A. The Plaintiff’s assertion that the Defendant concluded the instant contract with C, a general manager of the instant construction work, by leaving the Plaintiff’s executive C and the instant construction work cost.

The portion of the contract of this case concerning the unsatisfy construction cost is invalid as a false declaration of agreement.

Since the defendant has the duty to return part of the overpaid construction cost to C, but the remaining amount not returned to C is obligated to return it to C in unjust enrichment, the defendant shall be entitled to recover KRW 10,000,000 as part of that duty.

B. Prior to judgment.