法律行为被认定为无效后的已给付利益清算

日本民法中的不当得利制度系借鉴德国民法和瑞士民法的规定设计而成,以衡平说居于重要地位,但随着实践的发展,类型论亦逐渐获得一定判例的支持,因此应当进一步从法律事实与纠纷解决的角度对不当得利制度进行深入研究。同时,"法律行为被认定为无效后的已给付利益清算"问题属于与非债清偿并列的"给付得利"中的典型问题。值得关注的是,近年来在日本民法(债权法)的修改过程中,有学者提出无效法律行为的效果将会对不当得利法的理论与实践产生重要影响,因此,厘清当事人行为的各异样态、被认定为无效的诸种原因、以及所涉及的受领给付返还原则、价额返还原则、约定对价的限度等问题及其之间的关系尤为必要。目前日本民法(债权法)修改方案中的相关条文设置无法有针对性地解决实践问题,故此,最有效的立法方式应当是先将概括性的一般规定作为不当得利返还请求权的基础性条文,然后再针对个别类型通过特则进行具体规定。

Settlement of Interests Based on Performance after a Juristic Act Held Invalid

Unjust enrichment in Japanese Civil Code is designed by using provisions contained in German and Swiss civil laws,with equity playing a significant role.However,the notion of categorization has gradually gained support from certain cases in practice.We,therefore,should conduct in-depth study on unjust enrichment from the perspectives of legal fact and dispute settlement.Meanwhile,"settlement of interests based on performance after a juristic act held invalid" is a typical issue within the category of "enrichment based on performance" which is placed on a par with non-debt settlement.In recent years,during the course of revising civil code(law of obligations) in Japan,some scholars have noted that the effect of invalid juristic act may produce great impact on theory and practice with regard to unjust enrichment law.As a result,it is necessary and important for us to clarify various forms of acts by parties,different factors giving rise to invalidity,and issues involved such as principles of restitution of recipient of performance,restitution of money paid and limit of agreed consideration and relations among them.Currently,since articles drafted in revised version of Japanese Civil Code can not tackle practical problems with a clear aim,the most effective legislative approach should be adopted as follows.First,take the general rules as the basic articles involving the claim for restitution of unjust enrichment,and then prescribe specific rules targeting on particular category through special stipulations.