Santé publique France conducted a special COVID-19 edition of the Gender-Based Survey (ERAS) to assess the perceived impact of the COVID-19 health crisis on the living conditions, use of specific healthcare services, and sexual behaviors of men who have sex with men (MSM) during the lockdown period. ERAS is a cross-sectional, anonymous, self-administered online survey based on voluntary participation. Its special Covid-19 edition was conducted from June 30 to July 15, 2020. A total of 8,345 MSM residing in France were included in the analysis. Given their relatively privileged living conditions, the lockdown proceeded under fairly good conditions for a large proportion of respondents. However, negative impacts were observed economically, with some respondents experiencing a deterioration in their financial situation, as well as in terms of substance use and mental health. While these last two dimensions are not unique to MSM, they appear to be more pronounced than in the general population. Regarding the continuity of care for other health issues, 35% of respondents foregone care and 28% postponed their HIV/STI testing. Similarly, 34% of HIV-positive individuals postponed an HIV follow-up appointment. These impacts were likely mitigated by the implementation of telemedicine and the extension of prescriptions. Finally, 60% of respondents did not have sex with casual partners, and 59% of pre-exposure prophylaxis (PrEP) users stopped taking it due to a decrease in sexual activity, indicating compliance with social distancing measures but also a sudden halt in sexual socializing. Thus, the health crisis highlights the specific pre-existing health vulnerabilities of gay and bisexual men: isolation, mental health, and substance use, compounded by socioeconomic vulnerabilities.