Daniel Guérin (1904-1988), a marxist intellectual and anarchist activist, is a central figure to understand some transformations of the social representations of homosexuality in France from the 1950s to the 1980s. Guérin embodies the passage of one universe of discourse (i.e patterns of communication) to another, from the Arcadian legalism to the revolutionary speech of the FHAR – in other words from discretion to politicization. He developed an original theory of homosexuality, referring to a primary bisexuality. His reflection on the social and historical transformations of the homosexual identity inscribed the question of sexual identities in a nominalist perspective. In the 1950s and 1960s, Guérin’s writings dealt with the repression of homosexuality in France. He also gave his own analysis of the “sexual revolution” of the 1970s. His literary or public interventions, which form varied according to the contexts and times, encouraged the political demands of homosexuals, who were both stigmatized and repressed by the law and the police. Nevertheless, from the end of the 1970s to his death, he harshly criticized the progressive “essentialisation” of homosexuality, which was interpreted as a natural identity by activists.