The Parties' Unawareness of Inconsistent Regulatory Changes in Contractual Agreements

This study examines the Indonesian law of obligations under Book III of the Indonesian Civil Code (KUHPerdata) in comparison with the Dutch Nieuw Burgerlijk Wetboek (NBW), focusing on the binding force of contract, freedom of contract, and consensualism. In practice, contracts are often disrupted by default (wanprestasi), while scholars remain divided on whether Article 1266 of the KUHPerdata is mandatory law (dwingend recht) requiring judicial termination or supplementary law (aanvullend recht). This uncertainty encourages unilateral termination that may qualify as an unlawful act under Article 1365. Using a normative-empirical method, this study analyses the dispute between PT Mulia Realty Batindo and PT Batama Nusa Permai over the Bukit Palem Permai Project, decided in Decisions No. 15/Pdt.G/2022/PN Btm, No. 164/PDT/2022/PT PBR, and No. 975 K/Pdt/2023. The findings show that the Supreme Court majority accepted Batam Land Office Circular No. 246/640/VIII/2006 as a governmental act (fait du prince) excusing the developer from liability for default, supported by the parties' addendum, good faith, and public policy. No negligence existed when the contract was concluded in 2004; the real problem arose after 2006, when unilateral termination contradicted the jointly agreed addendum.