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

The grounds of appeal are examined.

1. Regarding ground of appeal No. 1

A. The right to impose and collect indemnity under Article 51(1), (4), and (5) of the former State Property Act (wholly amended by Act No. 9401, Jan. 30, 2009; Articles 72(1) and 73 of the current State Property Act) differs from the legal nature of the right to claim restitution of unjust enrichment under the civil law. As such, the State may file a lawsuit claiming restitution of unjust enrichment under the civil law against a person occupying without permission, separate from the exercise of the right to impose and collect indemnity.

(see Supreme Court en banc Decision 2011Da76402, Jul. 16, 2014). Furthermore, the right to impose and collect indemnities and the right to claim restitution of unjust enrichment under the civil law concurrently exist within the same amount, and the right to claim restitution of unjust enrichment under the civil law is extinguished when the right to claim restitution of unjust enrichment under the civil law is satisfied.

B. Review of the reasoning of the lower judgment and the record reveals the following facts.

(1) From December 3, 2002 to February 6, 2010, the Plaintiff occupied and used the instant real estate owned by the Republic of Korea without permission, and the Defendant imposed and collected indemnities on the Plaintiff four occasions on the premise that the Plaintiff occupied the instant real estate without permission.

(2) In addition to the above disposition, the defendant filed a lawsuit against the plaintiff on January 23, 2009 against the plaintiff on January 23, 2004 to the end date of possession of the defendant (hereinafter "related lawsuit"). On October 28, 2009, the court rendered a judgment that "the plaintiff shall pay the plaintiff the amount calculated at the rate of 5% per annum from January 23, 2009 to February 4, 2009, 20% per annum from the next day to the day of complete payment, and 316,406 won per annum from January 23, 2009 to the end date of possession of the real estate of this case."