The European MSM Internet Survey 2017 (EMIS-2017) on the behaviors of men who have sex with men was designed to collect data to inform the planning of prevention and treatment programs for HIV and sexually transmitted infections (STIs). The EMIS-2017 survey was coordinated by the SIGMA Research group at the London School of Hygiene and Tropical Medicine. The EMIS-2017 survey was conducted in 50 countries. The French edition of EMIS-2017 is the result of a partnership between the organizations AIDES, Coalition PLUS, and Santé publique France. EMIS-2017 is a cross-sectional survey whose data were collected using a self-administered, anonymous online questionnaire. The survey took place from December 19, 2017, to January 30, 2018. The questionnaire primarily addressed sexual and preventive behaviors regarding HIV and other STIs, drug use, and physical and mental health. Respondents were recruited via gay dating platforms and apps, LGBT+ organization websites, and social media. In France, 10,996 MSM participated in the survey, and 9,782 were included in the analyses. The sample of respondents for the EMIS-2017 survey consists almost exclusively of cisgender men, the majority of whom were born in France, with a median age of 38, living in urban areas, educated, employed, and not facing acute financial difficulties. The majority identified as homosexual, and their social circle was aware of their sexual orientation. More than one-third of respondents reported being in a stable relationship, the majority of which were with a man. Regarding knowledge of respondents’ HIV status and their use of testing, 12% reported being HIV-positive; three-quarters had taken at least one HIV test in their lifetime and reported being HIV-negative, while 12% had never received test results. The majority of respondents living with HIV (94%) reported having an undetectable viral load. Among respondents who reported not having received an HIV diagnosis at the time of the survey, 9% indicated they had previously used PrEP. In terms of sexuality, the majority of respondents were sexually active. In the past 12 months, nearly half (48%) reported having had sex with one or more stable male partners, and a large majority (84%) with one or more casual male partners. Among the latter, 52% had had 10 or more partners during that period. Only 9% of respondents reported having had sex with one or more women in the past year. Preventive behaviors varied depending on the type of partner and reported HIV status. While three-quarters of respondents reported not using condoms during sex with their steady partner, half of respondents having sex with casual partners fell into this category. The majority of HIV-positive respondents and those whose last test was negative while on PrEP reported not using condoms during sexual intercourse, whether with their steady partner (81% and 86%, respectively) or casual partners (82% and 87%, respectively); condoms were being replaced by biomedical prevention (Tasp for Treatment as Prevention and PrEP). For non-PrEP users whose last test was negative and those who had never been tested, condom non-use with steady partners was 74% and 63%, respectively, and with casual partners it was 47% for both groups. Use of psychoactive substances was significant. Regarding tobacco, nearly half of the respondents reported having smoked within the past year. Alcohol was the most commonly used substance, most frequently consumed within the past year and in the past four weeks. On the CAGE-4 scale, nearly 17% of respondents scored in the category indicating a risk of alcohol dependence. Furthermore, nearly one-third of respondents reported having used cannabis and almost 10% reported using ecstasy or GHB in the past 12 months. As for the practice of chemsex in the past 12 months, it was reported by 14% of respondents. Mental health indicators point to problematic situations. While a small proportion of respondents showed “strong signs” of anxiety (6%), nearly a quarter reported having had suicidal thoughts in the past two weeks. The level of internalized homophobia was low. However, 68% of respondents reported having been victims of homophobic acts during their lifetime, and nearly one-third within the past 12 months. Although methodological limitations inherent in this type of voluntary survey prevent the results from being generalized to the entire MSM population, the data collected by EMIS-2017 are valuable for developing interventions and campaigns to prevent HIV and promote sexual health among MSM: many challenges remain to be addressed.