1. In a claim for damages due to nonperformance, if the obligor fails to perform the contractual obligation in accordance with the terms and conditions of the established obligation, it itself is deemed unlawful (see, e.g., Supreme Court Decision 2000Da47361, Dec. 27, 2002). However, in a case where the obligor’s intention or negligence is not caused by nonperformance, the obligor is not liable for damages (see Article 390 of the Civil Act). Meanwhile, in a case where the obligor believed that the obligor has no contractual obligation and there is a justifiable reason for such belief, it may be deemed that the obligor falls

However, even if the obligor had asserted it through a lawsuit with the belief that he/she did not have a debt through a legal judgment on the cause or existence of the debt, if such legal judgment of the obligor was erroneous, barring any special circumstance, it cannot be said that there was no intention or negligence on the part of the obligor with respect to the default.

2. The lower court: (a) the Plaintiff is a housing redevelopment and rearrangement project association established for the purpose of implementing a housing redevelopment project with respect to 51,817 square meters in Jung-gu in Seoul, Jung-gu (hereinafter “instant project zone”); (b) the Defendants owned each of the instant real estate located within the project zone; (c) on January 19, 2007, the Plaintiff was deemed to have obtained consent to establish an association from 427 persons among 531 owners of the land, etc. located within the instant project zone; and (c) on October 13, 2007, the Plaintiff held a management and disposal general meeting on the management and disposal of 15-story apartment units on the ground and approved the management and disposal plan (hereinafter “instant management and disposal plan”) such as the content of newly constructing the total area of 15-story apartment units on the ground as 245,706,022,739, and the total area of 130,178 square meters on the ground that the Plaintiff and Dae forest industry company were designated as a contractor.