The Outermost Regions were recognised at the signing of the Maastricht Treaty in 1992, and confirmed by the Treaty of Lisbon in 2007. The Treaty on the Functioning of the European Union states that both primary and secondary European Union law applies automatically to the outermost regions, with possible derogations due to the particularities of these territories. The Overseas Countries and Territories are recognised by the Article 198 of the Treaty on the Functioning of the European Union which allows them to opt into EU provisions on the freedom of movement for workers and freedom of establishment, and invites them to join the Overseas Countries and Territories Association (OCTA) in order to improve cooperation with the European Union. The status of an uninhabited territory, Clipperton, remains unclear since it is not explicitly mentioned in primary EU law and has a "sui generis" status at the national level.