債權雙重讓與時，惡意債務人對後受讓人清償之效力──最高法院109年度台上字第2974號民事判決評釋

依最高法院105年度第15次民事庭會議決議，債權人就同一債權先後讓與不同受讓人者，第一受讓人取得債權；後讓與行為則為無權處分，非經第一受讓人同意，不生效力。
此時，如債務人明知債權經雙重讓與，卻向後受讓人清償，則債務人得否以該清償對抗第一受讓人？
就此問題，最高法院109年度台上字第2974號民事判決採肯定見解。
本文闡述德國民法、奧地利民法、瑞 士債務法、聯合國國際商事契約原則，及 歐洲契約法原則之相關立法例及學說，並 指出，最高法院前開判決錯誤適用民法第297條、第299條第1項，且明顯違反民法第310條第2款規定，更悖逆民法一再重申惡意當事人不受保護之重要原則，要難贊同。

According to the 15th Resolution of the Civil Senates Assembly of the Supreme Court in 2016, when a creditor assigns the same claim to different assignees, the first assignee acquires said claim; the subsequent assignment constitutes an unauthorized disposition and is not valid unless the first assignee grants consent.
In this event, if the debtor, with knowledge of the first assignment, renders performance to the subsequent assignee, a pertinent question arises: can the debtor employ that performance as a valid defense against the first assignee?
On this issue, the Supreme Court adopted a positive opinion in its 2020 Civil Judgment No. Tai-shang 2974.
This article elaborates the relevant provisions and legal doctrines of the German Civil Code, Austrian Civil Code, Swiss Code of Obligations, Unidroit Principles of International Commercial Contracts and Principles of European Contract Law. Based on the elaboration, the author underscores that the said Supreme Court’s judgment erroneously applied Article 297 and Article 299 Paragraph 1 of the Taiwanese Civil Code (TCC). Not only does the judgement contravene the provisions of Article 310 Item 2 of TCC, but it also conflicts with the fundamental principle repeatedly reiterated by TCC that a party acting in bad faith is not protected. As a consequence, reaching consensus with this judgment proves exceedingly challenging.