This thesis examines the repression of lesbian difference in the 1970s French women’s liberation movement (MLF) as a way of investigating the heterosexual complicity between French feminism and the French nation. Combining discourse analysis of archival materials and oral interviews, it seeks to explore how lesbian difference troubled the heterosexual order of 1970s French feminist discourses through an archaeology of the MLF’s (buried) controversies on lesbianism and a particular focus on Monique Wittig’s biographical and political trajectory. In conversation with queer theory, postcolonial studies, critical history and affect studies, this research argues that the political and affective transmutation of lesbians into (heterosexual) women, which is at the root of the MLF’s female universalism, was constituted through lesbian losses that melancholically haunted the 1970s as constant reminders of feminism’s exclusions. Conceiving of abstract universalism as a technology of power, the thesis first explains that feminists sought to absorb the nation’s sexual contract through the production of a feminist heterosexual contract, therefore hinging (heterosexual) women’s inclusion in the nation on lesbians’ illegibility. This “lie” or crisis in representation – claiming to represent all women while foundationally positing lesbians as non-women – was the paradoxical condition of the birth of a lesbian political subjectivity in 1970s France. Exploring lesbians’ affective, political and theoretical disidentification with feminism, the thesis then tracks lesbians’ melancholic traces in the archive as evidence of feminism’s failed lesbian history. Finally, it examines the return of the lesbian repressed, à contretemps, at the end of the decade, when a spectacular conflict broke out regarding lesbianism in the wake of Monique Wittig’s famous assertion, which was also a deferred exposure of the MLF’s founding lie: “lesbians are not women”. Revealing how the lesbian was made “un-French” in the 1970s (like queer theory today), this research seeks to understand her as a figure that troubles the heterosexual and colonial norms governing French abstract universalism and feminism’s attempts to reiterate it in a female form.