According to a paper by Lorraine M. Fleck,
No international treaty mandates the registration of scent marks. In fact, some treaties, such as Trademark Law Treaty, explicitly state the terms of the treaty do not apply to scent marks. Regarding national laws, some jurisdictions are more tolerant of scent marks than others. For example, the Australian trade-mark statute now expressly contemplates scent mark registration. The Sieckmann ruling has created a contradictory situation in Europe with respect to registration of scents under the European Community Mark (ECM) system. ECM applicants are not barred from applying for scent registrations, but simultaneously do not have readily apparent, acceptable methods to describe scent marks on trade-mark applications. Meanwhile, there are jurisdictions whose laws are silent on the registration of scent marks, such as Canada, and a number of countries (e.g. Brazil, China and Mexico) which forbid scent mark registration.