Introduction - The lockdown measures implemented in March 2020 to curb the spread of the coronavirus were accompanied by an increase in domestic violence affecting women, children, and lesbian, gay, and bisexual individuals. The objective of this study is to estimate the prevalence of domestic violence experienced by men who have sex with men (MSM) living with a family member during the first lockdown of 2020, to describe their characteristics, and to assess the health impacts. Methods - The Rapport au sexe Survey (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, by Santé publique France. A total of 8,345 MSM residing in France responded to the survey. Results - Among the 8,345 MSM respondents, 2,467 reported living in the same household as a family member during the eight weeks of the first lockdown. Of these, 35.2% (868) reported experiencing domestic violence during this period, primarily psychological verbal abuse. These men are characterized by their young age and precarious socioeconomic status. This hostile family environment had negative repercussions on their health, with one-third of them scoring high on measures of anxiety. Conclusion - The government has launched an emergency plan to combat anti-LGBT violence, but given the prolonged health crisis, innovative initiatives must be implemented to provide them with all the support they need.