Objective: To describe socioeconomic inequalities (SSE) in the prevalence and incidence of pharmacologically treated diabetes (PTD) in France in 2020. Materials and Methods: Individuals with PTD were identified in the National Health Data System. SEI was measured using the social deprivation index (FDep 2015) for municipalities of residence available in mainland France. The overseas departments (DOM) were studied separately. Prevalence/incidence rates were age-standardized (2013 European standard population). The denominators were all healthcare users (>99% of the French population). Results: The prevalence/incidence rates of DTP increased according to the FDep quintile (Q). The respective rates for women in Q1 (least disadvantaged) were 3.0% and 2.8 per 1,000 person-years (pa); for men, 5.1% and 4.4 per 1,000 p-years. In Q5 (most disadvantaged), the rates were 5.4% and 4.8 per 1,000 p-years for women; for men, 7.4% and 6.7 per 1,000 p-years. The Q5/Q1 ratio was higher among women (1.8 and 1.7, respectively) than among men (1.4 and 1.5, respectively). In the French overseas departments (DOM), the rates were even higher than those in Q5 in mainland France: among women (9.2% and 7.5 per 1,000 person-years) and among men (8.8%; 7.9/1,000 population). Discussion: Socioeconomic status (SES) remains a significant factor in the onset of type 2 diabetes in France in 2020, with a stronger association among women than among men. This study will be supplemented by an analysis of temporal trends in these SES indicators over the 2010–2020 period.