Reconstructing Legal Certainty in Marriage Agreements through Freedom of Contract and the Protection of Property Rights: An Analysis of Constitutional Court Decision Number 69/PUU-XIII/2015 regarding the Practice of Marriage Agreements in the City of

This study examines the reconstruction of legal certainty in marital agreements through freedom of contract and the protection of property rights following Constitutional Court Decision No. 69/PUU-XIII/2015, with particular reference to Tangerang City, Indonesia. The research employs a normative juridical method using statutory, conceptual, and case approaches, supported by qualitative doctrinal analysis of constitutional provisions, legislation, judicial decisions, and relevant legal literature. The findings demonstrate that the Constitutional Court's decision significantly expands contractual autonomy by permitting marital agreements before, at the time of, or during marriage. However, this flexibility introduces legal challenges concerning matrimonial property classification, retrospective contractual effects, creditor claims, and third-party protection. The analysis establishes that contractual freedom must operate within the requirements of legal validity, good faith, and constitutional property protection. Furthermore, notarial authentication and administrative registration are essential institutional mechanisms for strengthening legal transparency, although they do not automatically guarantee enforceability against third parties. The proposed normative framework integrates contractual autonomy, property rights protection, temporal certainty, institutional consistency, and legal harmonization. This study concludes that restoring legal certainty requires more than recognizing postnuptial agreements; it demands coherent contractual arrangements, consistent administrative procedures, and effective safeguards for existing legal interests. These findings contribute to strengthening Indonesia's matrimonial legal framework and provide normative guidance for marital agreement practices in Tangerang City.