Objectives - To analyze data from the surveillance of acute hepatitis B through mandatory reporting (MR) between 2003 and 2018. Method - Any case of acute hepatitis B, defined as the first-time detection of anti-HBc IgM, or HBsAg and total anti-HBc antibodies in the context of acute hepatitis B in the absence of IgM testing, must be subject to mandatory reporting. Results - A total of 1,788 cases of acute hepatitis B were reported between 2003 and 2018, with the annual number of cases declining starting in 2006 (185 in 2006 versus 59 in 2018), in a context of low reporting completeness, which nevertheless improved over time. The average age was 40.2 years, and 72% of cases were men. Only 64% of cases reported at least one risk exposure, the most common being sexual exposure (56%), particularly among men, and travel to an endemic area (33%). Among cases reporting a risk exposure, 81% were eligible for vaccination due to a particularly high risk, and only 5% were vaccinated. A majority of cases were hospitalized (65%), suggesting an overrepresentation of the most severe forms. Discussion - Conclusion - These data support a decrease in the incidence of hepatitis B, likely linked to vaccination strategies. They also provide information on the proportion of cases that could have been prevented by vaccination. However, given the lack of completeness (estimated at 27% in 2016), laboratory professionals and clinicians should be encouraged to report all cases they diagnose.