The protection of foreign property has been a key feature of CIL for at least the last century. The central protection under this regime is the MST. Still, the more specific investment protection regime reached its apex around 2010 with thousands of BITs in force. This article focuses on customary property protection, the scope of which exceeds that of BITs because it protects not only investors, but also any foreigner. To identify the relevant CIL rules, this article assesses the International Court of Justice Certain Iranian Assets case against the backdrop of previous cases. To this end, it first analyses elements characterized as CIL by the Court, eg police powers. Secondly, it deals with elements whose CIL character must be found between the lines of this case, such as the obligation to compensate indirect takings. Finally, it discusses legal questions the Court peremptorily set aside, for example whether assets’ blocking constitutes indirect expropriation.