The 2016 AfroBarometer is a cross-sectional survey combining self-collection of blood samples on filter paper with a self-administered questionnaire on a tablet computer. Its objective was to describe the sexual and preventive behaviors of Afro-Caribbean populations living in the Île-de-France region and to measure the observed prevalence of HIV and HBV infections in these populations. During May and June 2016, 1,283 people with a median age of 34—64% of whom were born in a sub-Saharan African country and the majority of whom were men (62%)—agreed to participate, representing 31% of those approached. The observed prevalence rates of HIV and HBV were 1.6% and 5.1%, respectively. Screening uptake appears insufficient both for HIV infection—where 40% of those infected were unaware of their status—and for HBV infection, for which 77% of HBsAg carriers were unaware of their diagnosis. Therefore, it is essential to expand screening services beyond current screening facilities and to promote the distribution and use of rapid diagnostic tests that combine screening for HIV and hepatitis B and C, along with clear and appropriate information and counseling.