Introduction - The health, economic, and social burden caused by mental disorders has helped make mental health a top public health priority. In France as well as abroad, the health crisis caused by the COVID-19 pandemic has had a significant impact on the mental health of the population. The objective of this study is to present findings regarding the prevalence of depressive episodes in metropolitan France in 2021 and to examine recent trends, particularly since the health crisis. Method - In 2021, the Santé publique France Barometer surveyed 24,514 people aged 18 to 85 via computer-assisted telephone interviewing (CATI) using a random sample. The short version of the Composite International Diagnostic Interview (CIDI-SF) questionnaire, developed by the World Health Organization, was used to measure major depressive episodes (MDEs) among respondents. Changes in the prevalence of CDEs were assessed in comparison with the 2005, 2010, and 2017 Health Barometers, which used comparable methodologies. Results - In 2021, 12.5% of people aged 18–85 reported having experienced a CDE in the past 12 months. Among those aged 18–75, prevalence increased by 3.5 percentage points, rising from 9.8% to 13.3%, over the 2017–2021 period. This increase applies to all analyzed population segments. The largest increase was observed among young adults (ages 18–24), with a 9-point rise between 2017 (11.7%) and 2021 (20.8%). In 2021, 18- to 24-year-olds, women, people living alone, and single-parent families—as well as those who reported financial difficulties, were unemployed, or indicated that COVID-19 had had a negative impact on their morale—had a higher risk of EDC. Conclusion - The prevalence of depressive episodes has increased in France. The trend, which began in 2010, accelerated at an unprecedented rate between 2017 and 2021, particularly among young adults. Stress caused by COVID-19 and the restrictions imposed to control it appears to be one of the main factors explaining this increase.