This study presents a comparative analysis of the legal rules and judicial practices of Iran and France concerning the expropriation of urban lands and the classification of mawat lands. It addresses the question of similarities and differences between the two systems in regulating the relationship between private property rights and public authority. The research hypothesis holds that France, benefiting from coherent legislation and stable judicial interpretations, provides greater consistency and predictability than Iran, where fragmented regulations and divergent judicial approaches weaken legal certainty. The study adopts a descriptive–analytical and comparative methodology based on documentary research, statutory analysis, and judicial precedents, drawing on principles such as proportionality, public interest, and the balance between public authority and private ownership. The findings indicate that the French legal system applies clearer and more objective criteria for establishing public interest and identifying lands subject to expropriation, while administrative courts actively review the legality and necessity of such measures. In Iran, despite several legislative interventions, ambiguities in defining mawat lands, varying interpretations of public necessity, and the absence of a specialized administrative judiciary have resulted in inconsistent rulings. Compensation mechanisms in France, grounded in the principle of full reparation, operate with greater efficiency and transparency, whereas valuation and compensation procedures in Iran lack uniformity and precision. Nevertheless, both systems seek to reconcile urban development with the protection of property rights. The study concludes that incorporating regulatory clarity and judicial coherence from the French model into Iran’s legal framework could improve expropriation procedures and criteria for lands.