The Unione Corse is a term designating the Corsican organized crime as a whole during the period 1930s–1970s, in the context of the French Connection, an international heroin trade network operated at that time between Turkey, Southern France, and the United States. A 1972 Time article described the "Unione Corse" as a Corsican-based unified and secretive crime syndicate akin to the American Five Families. The local situation in Southern France during this period was in reality more complex, with a nebula of mainly Corsican and Italian-French clans cooperating or fighting each other according to the circumstances and opportunities. If they constituted a key element of the wider French Connection, flooding the American market with Marseille-produced heroin from the 1950s to early 1970s, those clans remained overshadowed by the much more powerful Italian-American Mafia.

The French Connection was a scheme through which heroin was smuggled from Indochina through Turkey to France and then to the United States and Canada. The operation started in the 1930s, reached its peak in the 1960s, and was dismantled in the 1970s. It was responsible for providing the vast majority of the heroin used in the United States at the time. The operation was headed by Corsicans Antoine Guérini and Paul Carbone. It also involved Auguste Ricord, Paul Mondoloni and Salvatore Greco.