Preventing HIV infection is the cornerstone of the fight against the epidemic. In addition to condoms, other tools are now available, notably pre-exposure prophylaxis (PrEP) through antiretroviral treatment (emtricitabine-tenofovir disoproxil fumarate, initially available under the brand name Truvada® and in generic forms since March 2017), which, when taken before engaging in risky sexual activity, reduces the risk of HIV infection. The objective of this article is to assess the knowledge and use of PrEP among men who have sex with men (MSM) frequenting gay social venues in five French cities during the last quarter of 2015, prior to the implementation of the temporary recommendation for use (RTU) of Truvada® for this indication. Prevagay 2015 is an anonymous, randomized HIV seroprevalence study that collected behavioral questionnaire data and blood samples from MSM frequenting bars, saunas, and backrooms in five French cities. A total of 2,164 HIV-negative MSM residing in France were included in this analysis. Among them, 53% reported being aware of PrEP, primarily men surveyed in Nice or Paris, aged 25 or older, and with a college education. Furthermore, 2.3% reported having used this preventive treatment in the past 12 months. The majority of them had obtained PrEP by participating in the Ipergay trial (29%) or through a doctor’s prescription (27%). The suboptimal level of awareness of PrEP can be explained by the fact that the study was conducted before Truvada® was approved for routine use and thus before institutional information campaigns. However, given that this is a population exposed to prevention messages, these results encourage the continuation of information campaigns on all prevention tools, targeting all MSM populations—particularly those furthest removed from the gay community—so that everyone can make informed choices about their protection.