[2] The case holding that where a contractor of a newly built apartment house leases part of the apartment house to a third party without having completed the registration of ownership transfer in lieu of the payment of the construction price, the owner cannot make a request for surrender or unjust enrichment based on ownership to the third party, and the same applies even if the contractor fails to perform the obligation to pay money in the concurrent performance relationship with the owner's obligation of ownership transfer registration

[2] The case holding that where a contractor of a newly built apartment house leases part of the apartment house to a third party without completing the registration of ownership transfer in lieu of the payment of the construction cost, the owner cannot make a request for surrender or unjust enrichment based on ownership to the third party, and the same applies even if the contractor fails to perform his/her obligation to pay money in the concurrent performance relationship with the owner's obligation of ownership transfer registration.

Even if a purchaser of land has not yet completed the registration of ownership transfer, it shall be deemed that the effect of a sales contract has the right to possess and use the land, and it is reasonable to view that a purchaser of the land has again acquired the right to possess and use the land from the purchaser. As such, the seller cannot claim a return of unjust enrichment on the ground that the purchaser of the land has a real right right to the purchaser who again purchased the land from the purchaser or has no legal ground to occupy and use the land (see, e.g., Supreme Court Decisions 95Da12682, 12699, Jun. 25, 1996; 97Da42823, Jun. 26, 1998). This legal principle applies likewise to cases where a person to whom the ownership of the real estate, such as the sale and purchase, is already occupying and using the real estate, or is occupying and using the real estate again by leasing it.

The judgment of the court below is based on the following facts: (1) the plaintiffs 1 and 8 (hereinafter "the plaintiff, etc.") were filed for the above 9-year construction contract with the non-party 1 and the non-party 2 were the owners of 8-household houses located in Seocho-gu ( Address omitted); (2) the non-party 1 and the non-party 15-household houses (hereinafter "the non-party 1") were to be newly constructed on May 30, 192; and (3) the non-party 1 and the non-party 2 were to move the above 9-year construction contract with the non-party 4 to the non-party 9-year construction contract with the non-party 1 and to the non-party 2 for the above 9-year construction contract with the non-party 1 and the non-party 2 were to move the above 9-year construction contract with the non-party 2 to the non-party 3-party 1 and the non-party 9-party 1 and the non-party 9-party 1.

Then, in light of the legal principles as seen earlier, even if the Plaintiff et al. still failed to perform the obligation to transfer ownership to five households in the dispute of this case, and is the owner thereof, the Plaintiff et al. may not file a claim against the Defendants who leased and possessed the aforementioned right in the process of implementing the said payment in substitutes agreement from Nonparty 2, who was entitled to possess and use it, and a claim for return of unjust enrichment for possession and use thereof.

In addition, even if there was a simultaneous performance relationship between the obligation to be borne by the plaintiff et al. against the non-party 2 and the obligation to liquidate money between the non-party 2 and the plaintiff et al. in a previous lawsuit between the non-party 2 and the non-party 2, there is no room for recognizing the right to defense of simultaneous performance with regard to the part that can be

Furthermore, the special terms and conditions stipulated in the above contract between the plaintiff et al. and the non-party 2 are effective only between the non-party 2 as long as it is deemed that the lease act of this case against the defendants by the non-party 2 was done in the position of the claimant for ownership transfer under the above payment agreement in lieu of whether it was bona fide or not.

Ultimately, the reasoning of the judgment below is somewhat different, and the conclusion of rejecting all the plaintiffs' possession of five households in the dispute of this case based on the ownership of the five households in the dispute of this case on the ground that the above 7 households, including five households in the dispute of this case, was concluded with the plaintiff and the non-party 2, is justifiable, and it is not erroneous in the misapprehension of legal principles of simultaneous performance, or in the misapprehension of legal principles as to the defendants' bad faith as to the special agreement of this case, which affected the conclusion of the judgment. Thus, all of the arguments in the grounds of appeal are not acceptable.

Therefore, all appeals are dismissed, and the costs of appeal are assessed against the losing party. It is so decided as per Disposition by the assent of all participating Justices on the bench.

Justices Song Jin-hun (Presiding Justice)