The Communist Party of Fiume (Italian: Partito Comunista di Fiume – Sezione della III.a Internazionale) was instituted in November 1921, after the proclamation of the Free State of Fiume created by the Treaty of Rapallo. The Communist Party of Fiume was the smallest Communist Party in the world at the time. It was founded following the principles of the Third International, according to which each sovereign State had to have its own Communist Party organization.