‘동시이행항변권과 부당이득’의 몇 가지 쟁점에 관한 소고

If one of the parties has rescinded the contract, each party shall be liable to restore his other party to his original position(Para 1 of Art. 548 of the Korean Civil Act). While if a bilateral contract is void, each party shall be bound to return benefit which received by the other party's performance(Art. 741 of the Korean Civil Act). In the latter case, amount of benefits to be returned by person enriched will vary depending on whether he is a good faith or not. On the other hand, in case of rescission, the parties to a bilateral contract shall be liable to return the fruits and interest which acquired by benefit that the other party's performance, irrespective of good faith. I consider that amount of benefits to be returned of rescission and voidance should be the same in order to avoid unreasonable results. To put it in a nutshell, if a bilateral contract null and void, each party shall be bound to return such benefit by not Art. 748 of the Korean Civil Act but Art. 548 of the Korean Civil Act. Lessee may ask the lessor to purchase buildings on land remaining after the expiration of the period of the lease of land. He may refuse performance of his own obligation until the leaser pay the purchase-price. Thus, he shall have possessory right to both buildings and land by exceptio non adimpleti contractus(Art. 536 of the Korean Civil Act). However, if he's got a ‘real enrichment’ through possession, he shall be bound to return such benefit(Art. 741 of the Korean Civil Act). In other word, though lessee can use an object and take profits from buildings and land while exercising exceptio non adimpleti contractus, he must pay rent. By the way, he shall pay not ordinary rent which he will have to pay if a land lease contract but rent considering the special circumstances. The latter is cheaper than the former.