限制抵押財產轉讓約定的法律效果

《民法典》第406條在抵押人自由轉讓抵押財產的基礎上，允許當事人約定限制這種自由。約定禁止轉讓抵押財產的，為絕對限制；約定以抵押權人同意等為抵押財產轉讓條件的，為相對限制。在不動產抵押，絕對限制與《民法典》第406條的目的相悖，應當無效；相對限制一經生效，能約束抵押當事人雙方，但該約定未經登記，不得約束抵押財產受讓人、登記機構等第三人，即便不具備抵押權人同意等條件，亦不影響抵押財產的轉讓，登記機構也能辦理轉移登記。在動產抵押，浮動抵押合同約定絕對限制的，產生非浮動抵押權，非浮動抵押合同的這類約定無效；相對限制無論如何都不能對抗符合《民法典》第404條規定的買受人，但在登記後能對抗其他受讓人。這些看法對最高人民法院「民法典擔保制度司法解釋」第43條有所細化、補充和調整。

"Article 406 of the Chinese Civil Code vested in mortgagors with freedom to transfer the mortgaged property, and this freedom can be restricted by parties' agreement. Absolute restriction means that the transfer of mortgaged property is prohibited in the agreement of the parties, while relative restriction means that the parties agree to use the mortgagee's consent as the condition for the transfer of the mortgaged property. For real estate mortgage, absolute restriction goes against the gist of Article 406 of the Civil Code, which shall be invalid. Once the relative restriction takes effect, it can only bind the parties of mortgage relationship and it shall not bind any third party, including the assignee or the registration authority without registration. Even without the consent of the mortgagee, the registration authority can also accept the transfer registration as it does not affect the transfer of the mortgaged property. For chattel mortgage, when a floating charge contract stipulates absolute restrictions, it turns into ''non-floating charge'', while such agreement of forbidding the transfer in a non-floating charge contract shall be invalid; the relative restriction agreement can oppose to the assignee described in Article 404 of the Civil Code under no circumstances, but it can oppose other assignees after registration. These views have refined, supplemented and adjusted Article 43 of Judicial Interpretation of Civil Code's Guarantee System of the Supreme People's Court."