Tangier Protocol

The Tangier Protocol (formally the Convention regarding the Organisation of the Statute of the Tangier Zone) was an agreement signed between France, Spain and the United Kingdom by which the city of Tangier in Morocco became the Tangier International Zone. 
The protocol was signed in Paris on 18 December 1923 and entered into force with ratification on 14 May 1924. Starting from 1929, Spain assumed the policing of the city. An international legislative body was created to govern the city. Spain occupied Tangier from 1940 to 1945, taking advantage of France's occupation by Germany in 1940. The status of the international zone remained until its 29 October 1956 reintegration with Morocco, following Morocco's independence that year.
After it came into force, the Protocol was also acceded to by Belgium, Netherlands, Portugal and Sweden.