Prohibition of Refund of Knowingly Unnecessary Performance: Interpretation and Application of Paragraph 4 of Article 1109 of the Civil Code of the Russian Federation

The controversial formulation of paragraph 4 of Article 1109 of the Civil Code was the reason for its incorrect application. This led to the idea of the need for a restrictive interpretation of this norm. This approach, which originated in jurisprudence, has now been largely overcome by it, but it remains predominant in legal doctrine. Meanwhile, judicial practice has not yet formed a unified understanding of paragraph 4 of Article 1109 of the Civil Code. The present research aims to study the relevance of rejecting a restrictive interpretation of paragraph 4 of Article 1109 of the Civil Code. The article examines the history, foreign analogues, the nature and practice of application of this norm. As a result of the work the conclusion is made about the necessity of an expansive interpretation of paragraph 4 of Article 1109 of the Civil Code as a particular manifestation of the principle of good faith and the prohibition of abuse of right. Keywords: unjust enrichment; defence to a claim; no mistake in the victim’s actions; good faith; prohibition of abuse of right; estoppel.