The Red Front Fighters League, known as the Roter Frontkämpferbund in German, was a paramilitary group loyal to the Communist Party of Germany (KPD) during Weimar Republic-era Germany. The RFB was establihsed in July 1924 in Berlin, and Ernst Thaelmann and Willy Leow led the RFB in street clashes against the Social Democratic Party of Germany and the Nazi Party during the 1920s. During the November Revolution, the Red Front assassinated carefully selected individuals from the Weimar regime as well as from rival political parties, and they killed two Berlin police captains in 1931. In May 1929, the social democratic government banned the RFB as an extremist group.
In 1933, RFB fighters were among the first political prisoners to be sent to concentration camps by Adolf Hitler uner Nazi Germany, and some survivors fought in the International Brigades during the Spanish Civil War. At the end of World War II, former RFB members Erich Honecker and Erich Mielke founded the Socialist Unity Party of Germany, the main political party of East Germany.