1. In order for a contractual clause to be deemed null and void on the ground that it is a clause that is unreasonably unfavorable to a customer pursuant to Article 6(1) and (2)1 of the former Regulation of Standardized Contracts Act (amended by Act No. 10169, Mar. 22, 2010; hereinafter referred to as the “former Regulation of Standardized Contracts Act”), the contractual clause is somewhat disadvantageous to a customer. It is insufficient to say that the contractual clause is somewhat unfavorable to the customer. It is not sufficient that the contractual contractor abused his/her position in a transaction to make and use the contractual clause against the legitimate interests of the contractual party and reasonable expectations, thereby impairing the sound trade order. Whether the clause constitutes “unfair unfavorable to a customer” should be determined by comprehensively taking into account all the circumstances, such as the content and probability of disadvantage that may arise to the customer under the contractual clause, influence on the parties in the transaction process, and the provision of related Acts and subordinate statutes, etc. (see, e.g., Supreme Court Decision 2008Da13684, Dec. 27, 2016).

2. In light of the following circumstances, the court below held that the sales contract of this case where Article 5 (1) of the sales contract of this case, which provides for the settlement of rental deposit in accordance with the rent size of the store allocated after drawing lots, has lost fairness in violation of the principle of good faith, or has violated the duty to explain important contents of the terms and conditions to the defendant, who is the customer, so the above provision is null and void under the former Terms and Conditions Regulation Act, and thus the above provision should be revised to be applied only within the scope of the increase or decrease of the public area in proportion to the increase or decrease of the exclusive use area, and determined that the rental deposit of this case should be adjusted in proportion to the increase or decrease of the rent area (the same shall apply to

① Article 10(1) of the Act on the Ownership and Management of Aggregate Buildings (hereinafter referred to as the "Act on the Ownership and Management of Aggregate Buildings") provides that "the common use area belongs to the co-ownership of all sectional owners." Article 12(1) provides that "The shares of each co-owner shall be in proportion to his/her section of exclusive ownership." Since the common use area of a sectioned store is usual transaction practice, it would be in proportion to the ratio of the area of the section of exclusive ownership, the increase and decrease in the common use area would be expected to be in proportion to the increase and decrease in the area of exclusive ownership if the average and reasonable customer would normally have been in proportion to the increase and decrease in the area of exclusive ownership. On the contrary, it is very

② Since the instant sales contract does not provide for the criteria or method of calculating the leased area, if the language and text of the contract clause is interpreted as it is, it may cause unreasonable results contrary to the legitimate interests of the buyer and reasonable expectations by adjusting the rental deposit based on the “sale area plus an area that is not proportional to the increase and decrease of the exclusive use area that can be unilaterally determined after the contract by the business operator.”

③ Article 5(1) of the instant sales contract gives a business owner the right to unilaterally set standards for settlement after entering into a contract, so it is difficult for the purchaser to be unfairly disadvantaged in light of all relevant circumstances, such as the type of transaction of the contract, and it constitutes “a case where the seller grants a business owner the right to unilaterally determine or change the details of the payment without reasonable grounds” prescribed by Article 10 subparag. 1 of the former Act.

The plaintiff did not follow the purport of statutes, such as the Act on the Ownership and Management of Aggregate Buildings, and the principle of allocation of the common area according to the ordinary practices, and applied unilaterally separate standards established without the consent of the purchaser, and applied them to the separate standards, and requested settlement of the common area based thereon. In the process, the defendant et al. did not clearly

3. However, examining the following circumstances acknowledged by the court below in accordance with the legal principles as seen earlier, even if Article 5(1) of the sales contract of this case is interpreted in accordance with its language, it cannot be deemed as "a standardized contract which has lost fairness in violation of the principle of trust and good faith", and it cannot be deemed that the plaintiff violated its duty to explain as provided by the former Standardized Contract Regulation Act at the time of conclusion of the sales

A. The reasoning of the lower judgment and the evidence duly admitted by the lower court reveal the following.

① On September 2002, the Plaintiff entered into a comprehensive implementation contract for the reconstruction project with the said reconstruction association on the following occasions: (a) the Plaintiff was implementing a new construction project of a commercial building called “F” (hereinafter referred to as the “instant commercial building”) in Seoul Jung-gu E-gu, Seoul, where the land of the former C market was located; and (b) the Plaintiff entered into a comprehensive implementation contract for the reconstruction project with the said reconstruction association

② On September 28, 2006, the said reconstruction association opened an extraordinary general meeting of its members and made a resolution to include 1/2 of the passage area (so-called "sloping area") linked to each store in the common area of the relevant store when calculating the sale area, and to calculate the remaining common area in proportion to the exclusive area of the relevant store.

3) On May 13, 2008, the Plaintiff concluded the instant sales contract with the Defendant for the sale of the right of lease to the store of this case.

④ Article 1(1) of the instant sales contract provides that “The specific location of a store shall be drawn after payment of the balance, and the sales price shall be settled according to the size of the store determined by lot.” Article 4(1) of the instant sales contract provides that “The sales price of a store shall be calculated by adding the area for exclusive use to the area for exclusive use, and where there is an increase or decrease in the area for exclusive use after the drawing of a store, the sales price shall be adjusted in proportion to the increase or decrease rate.” Article 5(1) provides that “The buyer shall settle the rental deposit according to the rental area of the store allocated after drawing.”

B. According to the Aggregate Building Act, a section for common use, excluding a section for partial common use, belongs to the sharing of all sectional owners (Article 10(1)), and each co-owner’s share is in accordance with his/her ratio of the area of his/her section for exclusive use (Article 12(1)), and such matters may be separately determined by regulations (Article 10(2)). In real transactional relationship, where each co-owner’s share in the section for common use is not in proportion to the area of his/her section for exclusive use. In the case of a large-scale commercial building in which a large number of divided stores are located, the value of each individual store may vary considerably depending on their location. As such, reflecting the passage area adjacent to the relevant store in calculating the area for common use, which serves as the basis for

C. In the case of the instant commercial building, 1/2 of the passage area abutting on each sectioned store in calculating the sale area is included in the common use area of the relevant store, and the remaining common use area was included in the common use area of each sectioned store in proportion to its exclusive use area. This is not unilaterally determined for the benefit of one party, such as a business operator, etc., as matters determined through an extraordinary general meeting to resolve unfair trade among the reconstruction members who were in the position to be determined by the location of their own store through a lot of lot.

Furthermore, in light of the language, content, system, etc. of Article 5(1) of the sales contract of this case, it is evident that the rental deposit out of the sales contract of this case should be settled according to the leased area added to the exclusive use area. In addition, the above contents are general and common in the transaction, and thus, the Defendant also knew or could have anticipated it.

4. Nevertheless, the court below held that the construction of Article 5 (1) of the sales contract of this case in accordance with its stated reasoning is invalid in light of the purport of the former Act on the Regulation of Terms and Conditions, and thus, it should be interpreted that the rental deposit in the sales contract of this case should be computed at an increase or decrease rate of exclusive use area. Thus, the court below erred in the misapprehension of the judgment of the Supreme Court as stipulated in Article 3 (2) of the Trial of Small Claims Act. The ground for

5. Therefore, the lower judgment is reversed, and this part of the case is remanded to the lower court for further proceedings consistent with this Opinion. It is so decided as per Disposition by the assent of all participating Justices on the bench.

Justices Kim Jae-han

Justices Kim In-young

Justices Lee Dong-won