1. The Defendants shall jointly and severally pay to the Plaintiff KRW 25,00,000 as well as 20% per annum from August 1, 2013 to the date of full payment.

1. Basic facts

A. The Plaintiff is the implementer of the Do Building in Kim Sea-si, and the Defendants are the buyers of the 103th floor of the Do Building (hereinafter “instant real estate”).

B. On May 24, 2013, Defendant B entered into a sales contract with the Plaintiff to pay the remainder of KRW 400 million (hereinafter “instant first sale contract”) on July 31, 2013 (hereinafter “instant first sale contract”); Defendant B paid KRW 10 million on May 23, 2013; and the remainder of KRW 390,60,000 on May 37, 2013, in total, KRW 400 million.

C. On the other hand, the first sale contract provides that "if there is any increase or decrease in the sale area, it shall be settled at the remaining time" as the special agreement.

On June 20, 2013, the instant real estate obtained approval for use on June 20, and at the time, the sale area was determined as 102.76 square meters.

E. Accordingly, the Plaintiff prepared a sales contract with the Defendants stating that the Plaintiff shall pay late payment charges applying 20% overdue rate to the number of delayed days when the payment of the intermediate payment and the remainder is delayed (hereinafter “the second sale contract of this case”).

F. On August 9, 2013, the Defendants paid to the Plaintiff KRW 471,60,000 out of KRW 496,60,600,000, after deducting KRW 700,000,000, which the Plaintiff leased to Nonparty E with respect to the instant real estate from the remainder of KRW 566,60,000 according to the instant sales contract. On the same day, the Plaintiff completed the registration of ownership transfer for the instant real estate to the Defendants.

[Judgment of the court below] The facts that there was no dispute over the ground for recognition, Gap evidence 1 through 6 (including the number of branch offices; hereinafter the same shall apply), the purport of whole pleadings

2. Determination as to the cause of claim

A. The above facts of recognition.