미등기 건물의 토지 사용으로 인한 토지소유자에 대한 부당이득반환의무 -대법원 2022. 9. 29. 선고 2018다243133(본소), 2018다243140(반소) 판결의 검토-

In the Supreme Court decisions 2018da243133 (main action) and 2018da243140 (countersuit) issued on September 29, 2022, the issue was whether both the original acquirer of an unregistered building and the person with de facto power to dispose of it have an obligation to return of unjust enrichment to the landowner, or either party exclusively has an obligation to return of unjust enrichment. If the former position is taken, the question relates to the relationship between the obligation of the original acquirer of an unregistered building, to return of unjust enrichment and the obligation of the person with de factor power to dispose of the building, to return it. Regarding this issue, in the Supreme Court decisions 2018da243133 (main action) and 2018da243140 (countersuit) issued on September 29, 2022, it was held that the original acquirer of an unregistered building has an obligation to return of unjust enrichment to the landowner, and the original acquirer has a quasi-joint and several liability to return of unjust enrichment to the landowner. In this paper, to determine the validity of the Supreme Court decisions 2018da243133 (main action) and 2018da243140 (countersuit) issued on September 29, 2022, research was conducted in the following sequence. First, the status of the discussion of whether when the land is occupied, or used by an unregistered building, an occupier, or an use qualifies as an unregistered purchaser of the building, that is, whether the de factor right to dispose of the land by an unregistered purchaser of the building is recognized, was examined with a focus on whether the legal principle of “the de facto right to dispose” recognized by the precedents applies. Second, by examining the Supreme Court decision 2006da39157 issued on July 10, 2008, whose question was raised in the Supreme Court decisions 2018da243133 (main action) and 2018da243140 (countersuit) and the Supreme Court decisions 2009da76522 and 2009da76539 of July 14, 2011, I sought to identify a trend in the precedents related to the issue of this case. Third, based on the conclusion drawn by the research on the first research project described above and the analysis of a trend in the precedents related to the issue in this case, the validity of the Supreme Court decision of this case was examined. The Supreme Court decisions 2018da243133 (main action) and 2018da243140 (countersuit) issued on September 29, 2022 is significant in that it is the first ruling which recognized the occupation of the land site by a transferee (the person with the de facto right of disposal) of an unregistered building, which was built without a building permit, and acknowledged the obligation to return of unjust enrichment. The decision is meaningful in that it is a decision based on specific reasonableness in consideration of the fact that owners of most unregistered buildings built without building permits do not delay the registration, but rather they have no way of completing the registration process. With this ruling, it is hoped that in-depth discussions will take place at the academic level and with practitioners on relevant issues, including the relationship between an original acquirer of an unregistered building and a party with de facto right of disposal, in relation to the obligation to return of unjust enrichment to the land owner; the obligation of an original acquirer of an unregistered building to return of unjust enrichment to the land owner.