LOCUS REGIT ACTUM

locus regit actum (loh-k<<schwa>>s ree-jit ak-t<<schwa>>m), n.[Latin “the place rules the act”] Int’l law. The rule that a transaction complying with the legal formalities of the country where it is created will be considered valid in the country where it is to be effective, even if that country requires additional formalities.
[Blacks Law 8th]