1. The Plaintiff:

A. Defendant B and C are jointly and severally liable for KRW 570,000,000 and Defendant B.

1. Status, etc. of the parties;

A. The Plaintiff is an individual entrepreneur who operates the interior, etc. with the trade name of “E” and the Defendant B (hereinafter “Defendant Company”) is a corporation that conducts real estate development and sales agency business, etc., and the Defendant C is the representative director of the Defendant Company, and the Defendant D is an employee of the Defendant Company (chief of headquarters).

B. Around 2018, the Defendant Company planned to construct a model house (the model house; hereinafter “instant model house”) to publicize the regional housing association scheduled to build a house in the “F Il-si”. The Defendant Company planned to construct a model house (hereinafter “instant model house”).

【Ground for Recognition: Facts without dispute, Gap evidence 1, Eul evidence 2, and the purport of the whole pleadings

2. Determination as to the cause of action

A. Comprehensively taking account of the overall purport of arguments and arguments as to Gap's evidence Nos. 1, 2, and 4 as to the defendant company, the defendant company entered into an agreement with the plaintiff on June 26, 2018 at the time of being entrusted with the interior construction of the sample house of this case and at the cost of KRW 570,000,000 in return (hereinafter "the construction contract of this case"), and the plaintiff entered into the construction contract of this case at the time of the original city and completed the construction work agreed on November 3, 2018 and received a written confirmation of the completion of construction work from the defendant company.

Therefore, the Defendant Company claimed on January 4, 2019 for the Plaintiff the price of KRW 570,000,000 under the instant construction contract and the delay damages from November 4, 2019 [the Plaintiff claimed on the premise that the due date for the payment of the construction cost has arrived on the date the construction was completed, but the contract of the instant construction agreement stipulates that the “within two months after the opening of a model house model house model” shall be paid (see Article 2 of the said contract and paragraph (2) of the said special agreement) (see Article 2 of the said special agreement and Paragraph (3) of the said special agreement). Since the relocation of a model house is to proceed after the Defendant Company prepares a written confirmation of the completion of construction (see Paragraph (3) of the said special agreement,