All scientific indicators point to the same conclusion: the COVID-19 pandemic has taken a toll on the mental health of the general population, and particularly on certain groups: young people, women, and those in precarious situations. Young people (especially those aged 15–24) are the group with the highest levels of depressive symptoms. Another finding that highlights the impact of health determinants and inequalities: while students are certainly the group most at risk of depression throughout the COVID-19 health crisis, this risk is even higher among 18- to 24-year-olds who are neither in school nor employed, and among 25- to 30-year-olds who are unemployed. The factors most strongly associated with an increase in symptoms of depression or anxiety during the health crisis include a history of psychological difficulties prior to the pandemic and a deterioration in one’s professional and financial situation. These findings highlight significant social inequalities in mental health in the context of the COVID-19 pandemic, and the fact that certain population groups, such as young people or those who are not working, require special attention in terms of prevention and support.