Background: Medical students' mental health is a public health problem that has worsened with COVID 19's pandemic. There is a lack of French data. The principal aim was to assess French medical students' mental health. Methods: An online cross-sectional survey was performed between May 27 and June 27, 2021. An anonymous questionnaire was sent via academic email addresses by medical faculties and secondly on social media. We assessed 7-day anxiety and depressive symptoms were evaluated with the Hospitalization Anxiety and Depression scale, 12-month major depressive episode (MDE) with the Composite International Diagnostic Interview-Short Form, burnout with the Maslach Burnout Inventory, 12-month suicidal ideation, humiliation, sexual harassment, and sexual aggression during their curriculum. Multivariable logistic regression was performed to identify main MDE associated factors. Outcomes: 11,754 participants (response rate: 15.3%) were included. Prevalence of 7-day anxiety symptoms, 7day depressive symptoms, 12-month MDE, and 12-month suicidal thoughts were 52%, 18%, 25%, and 19% respectively. Burnout syndrome concerned 67% of clinical students and residents and 39% of preclinical students. Prevalence of humiliation, sexual harassment, and sexual abuse during their curriculum were 23%, 25%, and 4%, respectively. Having important (OR = 1.44, IC 95 [1.31-1.58], p < 0.001) or very important financial issues (OR = 2.47, IC 95 [2.15-2.85], p < 0.001), experienced humiliation (OR = 1.63, IC 95 [1.46-1.81], p < 0.001), sexual harassment (OR = 1.43, IC 95 [1.28-1.59], p < 0.001) and sexual abuse (OR = 1.52, IC 95 [1.24-1.85], p < 0.001) were associated with an increased risk of MDE. Interpretation: This is the largest study on French medical students' mental health. These results point to very particular conditions in French students environment that need to be addressed to improve their mental health.