Cocaine use in France has risen sharply over the past two decades, accompanied by a documented increase in prevalence, emergency visits, and hospitalizations for somatic and psychiatric complications. Its diffusion is not uniform but structured around social networks, specific festive contexts, and critical time periods—particularly late-night after-parties and private gatherings—which appear to play a central role in the initiation and normalization of use. Drawing on epidemiology and network theory, cocaine use can be understood through an epidemiological lens, where its spread depends on a social contagion threshold shaped by interpersonal interactions and peer reinforcement. Structural interventions targeting key network hubs and bridges—such as improving late-night public transportation to reduce high-risk transitions at the end of the night—represent promising avenues for public health prevention.