A. The Seoul Yangcheon-gu Seoul Metropolitan Government 106dong 701 (hereinafter “instant apartment”) originally transferred the right to sell the apartment in this case to the petitioner construction company, a contractor, as a payment in lieu of the construction cost. Around May 8, 2006, the petition construction company transferred the right to sell the apartment in this case to D designated by the said building company, a subcontractor, as a payment in lieu of the subcontracted construction cost. At the time of the transfer, the petition construction and D drafted a sales contract with the purchase price of KRW 239 million with the purchase price of KRW 29 million.

B. On November 24, 2006, the petition construction and the C reconstruction Association prepared a confirmation document on the completion of the sale price of the apartment in this case, confirming that the sale price of the apartment in this case was fully paid.

C. D, around December 30, 2006, sold the right to purchase the apartment of this case to the Defendant at KRW 200 million, the Defendant sold the right to purchase the apartment of this case to the Defendant, and the Defendant decided to offset the loan claim against the existing D, and paid the remainder KRW 150 million around January 10, 2007.

On November 3, 2009, the Defendant prepared an agreement settlement statement to pay the balance amounting to 40 million won with respect to the apartment of this case (hereinafter “each of the instant agreements”) and delivered it to the said association.

After that, the defendant completed the registration of ownership transfer on the apartment of this case on April 12, 2010.

E. Meanwhile, the Plaintiff, who had a claim for construction cost against C reconstruction Association, received KRW 37 million from among the claims on each of the instant notes owned by the said Association against the Defendant, and the Defendant paid KRW 10 million to the Plaintiff around September 2, 2013, and the remainder of KRW 27 million, which was filed by the Defendant against C Reconstruction Association at the time, within 15 days after winning a lawsuit for the registration of ownership transfer (Seoul Southern District Court 2013Da60269) regarding the site of the instant apartment.