All appeals are dismissed.

The costs of appeal are assessed against the plaintiffs.

The grounds of appeal are examined.

1. With respect to the grounds of appeal on whether the cost of creating a housing site excludes the cost of maintaining and managing facilities, other cost of installing public facilities, and disposal of the area of a site for sports facilities, if a person subject to relocation measures under a special supply contract for a resettled housing site concluded between a person subject to relocation measures and a project implementer included the cost of installing basic living facilities under Article 78(4) of the former Act on Acquisition of and Compensation for Land, etc. for Public Works (amended by Act No. 8665, Oct. 17, 2007; hereinafter “former Public Works Act”) in the sale price and thus the person subject to relocation measures pays the cost of installing basic living facilities to the project implementer, the part of a special supply contract that included the cost of installing basic living facilities in the sale price is null and void in violation

(See Supreme Court en banc Decision 2007Da63089, 63096 Decided June 23, 2011 (see Supreme Court en banc Decision 2007Da63089, 63096, supra). In a case where the sale price does not reach the cost of the housing site by setting a certain amount at a discount of the cost of the housing site development, the entire cost of the cost of the basic living facilities, which is a part of the cost of the housing site development, shall not be deemed to have been included in the sale price. The sale price exceeds the “amount obtained by deducting the cost of the basic living facilities from the cost of the housing site development” and the scope thereof shall be determined through mutual relations

Therefore, if the housing site development cost exceeds the “amount obtained by deducting the installation cost of basic living facilities from the housing site development cost,” only such portion constitutes unjust enrichment as the installation cost of basic living facilities included in the sale price.

(See Supreme Court Decision 2013Da29509 Decided July 23, 2015, and Supreme Court Decision 2014Da8997 Decided October 15, 2015). Here, “cost for housing site creation” refers to a project implementer’s relation.