My dissertation centers on literary representations of non-normative gender performances, the struggle around new gender norms, and the lived realities of gender in pre- and post-World War I- (WWI) era France. The novels discussed in this study, L'Immoraliste (André Gide, 1902), Chéri and La Fin de Chéri (Colette, 1920 and 1926, repectively), and Voyage au bout de la nuit (Céline, 1932) all depict how WWI significantly disrupted French life and troubled gender roles in nearly all environments. The novels that I analyze reveal, in particular, how French manhood became a source of nationalist anxiety in this era, as masculinity was seen as weakened by prior French military defeats and the so-called "excesses" of the belle époque. Using an interdisciplinary approach, the dissertation puts WWI-era novels in dialogue with the visual culture of war propaganda found in French government-sponsored propaganda posters. As I show, propaganda posters heavily promoted heteronormative standards of French masculinity, disseminated images of the ideal French male as physically powerful, courageous, and ready to defend family and nation, and reminded young French men that they carried the weight of defending not only the nation, but the future of French masculinity and the health of the population more broadly. As my study argues, novels by Colette, Gide, Celine, and others call into question WWI propagandized gender norms by imagining alternative gender performances and creating spaces for self-determined gender performances. My dissertation thus argues that novels by Gide, Colette, Céline, and others demonstrate that the normative standards encountered in WWI propaganda were, in fact, fictions that belied the lived realities of gender.