The appeal is dismissed.

The costs of appeal are assessed against the Defendant (Counterclaim Plaintiff).

The grounds of appeal are examined.

1. As to the ground of appeal No. 1 (the part on violation of the duty to protect the opportunity to recover premiums)

A. Article 10-4 of the former Commercial Building Lease Protection Act (amended by Act No. 15791, Oct. 16, 2018; hereinafter “former Commercial Building Lease Act”) provides that “The lessor shall not interfere with the receipt of premiums from a person who wishes to become a new lessee arranged by the lessee according to the premium contract by doing any of the following acts from three months to the expiration of the lease term to the expiration of the lease term (Article 10-4).” (Article 10-4) of the same Act provides that “The lessor shall not interfere with the receipt of premiums from a person who wishes to become a new lessee arranged by the lessee without any justifiable reason).”

(4) A lessor is liable for damages incurred to a lessee due to a lessor’s breach of his/her duty to protect the opportunity to recover premiums.

(3) Meanwhile, according to Article 33 of the Private School Act and Article 35(1) of the Financial Accounting Rules of a private school institution, where a school foundation intends to enter into a lease agreement exceeding KRW 50 million (based on annual or total amount), which is an amount under Article 26(1)5(a) of the Enforcement Decree of the Act on Contracts to Which the State Is a Party, it shall be referred to as a general competition unless there is any reason to conclude a free contract under Article 35(3) of the said Rules.

Thus, in a case where concluding a lease contract with a person arranged by a school foundation as a new lessee would violate the legal obligation to select a lessee by means of competitive bidding, barring any special circumstance, it should be deemed that there exists “justifiable cause” as stipulated in Article 10-4(1)4 of the former Commercial Building Lease Act to refuse to conclude a lease contract due to such circumstance.

B. The lower court is as indicated in its reasoning.