Objectives: 1) To estimate the incidence of diagnosed acute hepatitis B and the completeness of mandatory reporting (MR) of acute hepatitis B in France in 2013 based on the LaboHep survey; 2) To describe the epidemiological characteristics of reported cases of acute hepatitis B. Methods: The LaboHep survey was conducted among a random sample of 1,504 laboratories. An acute case was defined by the absence of known chronic carrier status and the first-time laboratory detection of anti-HBc immunoglobulin (Ig) M in 2013. The incidence of acute hepatitis B was estimated after multiple imputation of missing data and weighting. The analysis of DO data, whose case definition is broader than that of LaboHep, focused on cases diagnosed between 2012 and 2014. The completeness of the DO was assessed by comparing the number of anti-HBc IgM-positive cases reported by laboratory professionals (DO) in 2013 with the estimated number of "reportable cases" for 2013 via LaboHep. Results: In 2013, the number of diagnosed cases of acute hepatitis B is estimated at 291 (95% CI: [254–329]), corresponding to an estimated incidence of 0.44 (95% CI: [0.39–0.50]) per 100,000 inhabitants. The majority of cases were men (69% according to LaboHep 2013, 77% according to the DO 2012–2014), who were older on average than women (44 years vs. 37 years). Nearly 80% of reported cases for which at least one risk exposure was identified had an indication for vaccination. The completeness of the DO is estimated at 23.5%. Discussion: The incidence of diagnosed acute hepatitis B is low, but could be significantly reduced if vaccination recommendations were better implemented. The LaboHep surveys and the DO provide indirect indicators of the impact of the HBV vaccination policy.