The judgment below is reversed and the case is remanded to Seoul High Court.

The grounds of appeal are examined.

1. Case summary

A. The Plaintiff established the right to collateral security (the maximum bond amount of KRW 3.57 billion) on the instant real estate in B in order to secure the obligation for corporate facility loan to the Intervenor A (hereinafter “B”), a supplementary participant corporation succeeding to the Defendant (hereinafter “Nonindicted Company”) who was employed as the representative director, who established and operated medical welfare facilities for the aged under the former Welfare Act (amended by Act No. 10785, Jun. 7, 201; hereinafter “former Welfare Act”) and established the right to collateral security (the maximum bond amount of KRW 3.57 billion) on the instant real estate in order to secure the obligation for corporate facility loan to the Defendant’s supplementary participant B (hereinafter “B”).

B. As the non-party company, the borrower, was unable to repay its debts, the auction procedure for the real estate of this case was initiated upon the request of B, and the defendant succeeding intervenor acquired the right to the non-party company and the right to collateral security concerning the real estate of this case from B.

C. The Plaintiff, upon delegation of Article 35(3) of the former Welfare Act, prohibits the establishment of a mortgage on real estate where a medical welfare facility for the aged is established under Article 22(1) [Attachment 4] of the former Enforcement Rule of the Welfare of the Aged Act (amended by Ordinance of the Ministry of Health and Welfare No. 51, Apr. 15, 2011; hereinafter “former Enforcement Rule of the Welfare of the Aged Act”). Since this is a mandatory provision, a mortgage contract contrary thereto is invalid. The Plaintiff filed a claim against the Intervenor succeeding to the Defendant for the cancellation of the registration of the establishment of a mortgage prior to the establishment of a mortgage

2. Whether a prohibition provision of the Enforcement Rule, which the Plaintiff gets internal tax, is a mandatory provision

A. In a case where a contract or other legal act is performed in violation of a specific legal provision prohibiting a certain act, whether such legal act is null and void or the court shall assist in realizing the contents of the legal act.