Economic equilibrium between the considerations (counter-prestations) is a cornerstone of the stability of onerous contracts; in various legal systems, this concept is addressed under the rubric of *ghabn* (lesion or gross disparity in value). This study, employing a descriptive-analytical approach, aims to elucidate the rules governing the rescission of contracts due to an imbalance in the value of the considerations under both Iranian and French law. It specifically addresses the question: what are the similarities and differences between the rules regarding contract rescission due to *ghabn* in these two legal systems? The findings indicate that in Iranian law, *ghabn*—grounded in the principles of "commutative justice" and the maxim of "no harm" (*la-darar*)—serves as a general rule, granting the disadvantaged party the right to rescind the contract (*khiyar-e ghabn*) in all onerous contracts, provided the disparity is substantial. Conversely, French law—prioritizing the autonomy of the will and the stability of contracts—does not recognize *ghabn* as a general principle; rather, it permits intervention in a contract only in specific, legally enumerated instances, such as transactions involving immovable property or the protection of legally incapacitated persons. The divergence in the underlying rationales, scopes of application, and legal remedies between these two systems reflects a prioritization of individual justice within Iranian law, as opposed to legal certainty within French law.