Left-wing fascism

Left-wing fascism (or left fascism) is when left-wing politics emulate and practice the traditional ideology of standardised fascism on the far-left side of the political spectrum. Fascism has traditionally been identified as being part of far-right politics. The existence of left-wing fascism was discussed shortly after World War II where many Social-Nationalist groups across Europe were identified as having left-wing ideals, some in direct opposition to right-wing groups.
Left-wing fascism has been long discussed academically and written about by researchers like Jürgen Habermas, Irving Louis Horowitz, and Victor Klemperer.