摘要：

合同无效且有给付时，《民法典》总则编第157条的“返还财产”可为物权性救济，亦可为债权性救济。尤其当合同旨在发生物权变动而未完成公示之时，成立返还原物请求权；反之，成立不当得利请求权。是否承认物权行为并不影响上述规则的适用。合同类型的差异对无效后返还请求权的确定具有决定意义，其请求权依据，或系于物权法，或系于不当得利法或合同法，故第157条无法作为独立的请求权基础。返还形态上，以实物返还为原则、价值返还为补充，但当事人可就返还形态为特别约定。《民法典》合同编实现了对不当得利法的更新扩容。解释上，得利人返还的范围包括现存得利和孳息，并得考虑得利人的主观状态，若属恶意，更应返还那些本应收取却未收取的孳息。

关键词: 合同无效, 不当得利, 原物返还, 价值返还, 《民法典》合同编

Abstract:

If a contract which includes a payment is null，the rule of Article 157 of the Civil Code of PRC“restitution of property”can be the relief of real right，or the relief of obligation.In particular，when the contract is aimed at the transfer of ownership，and its public notice is not completed，the claim for recovery shall be established，on the contrary，the claim for unjust enrichment shall be established.Recognizing or not the theory of Act of real right does not affect the application of the rules mentioned.Under conditions of nullity，the difference of contract type is decisive to the determination of the claim of restitution.The right of claims derives from property law or unjust enrichment law，or contract law，therefore，the Article 157 cannot be used as the basis of the independent claim.In terms of forms of restitution，the restitution in kind is the principle and restitution in value is the supplement，but the parties may make a special agreement on the form.The Contract Part of Civil Code realizes the renewal and expansion of unjust enrichment law.From the perspective of interpretation，the scope of restitution for the recipient includes the extant enrichments and the fruits，meanwhile，its subjective state should be considered.If malicious，he should return the fruits that should have been collected but not collected.

Key words: Nullity, Unjust Enrichment, Recovery, Restitution in Value, Contract Part of Civil Code