A court deciding a case between parties residing in different States must determine which State law is applicable. This provision is often referred to as „choice of law.“ If the contract is not a choice of law, the court will generally use the law of the State in which the transaction was entered into or in which a substantial part of the subject matter of the contract is to occur. However, if the treaty determines which state laws govern disputes, the courts will comply with those provisions. Interestingly, parties to a contract established in the same state may order courts to apply the law of another state to settle disputes. [Updated June 13, 2017: Triggered by this recent contribution, I changed my mind. I think it should be a language of the declaration: the parties acknowledge that this agreement does not regulate the law that governs disputes arising from this agreement or the subject matter of this agreement. What for? Indeed, there is no real sense in indicating as a basic rule of the Treaty what the Treaty does not cover. But maybe I`m pedantic. And in any case, there is no possibility of confusion.] While there is no jurisdiction clause, complex rules and instruments apply, which vary depending on whether or not the court has its seat in Europe. .