This article provides an overview of HIV testing activity in France in 2018 in clinical laboratories and the circumstances surrounding the detection of HIV-positive cases based on mandatory HIV reporting. In 2018, 5.80 million (95% CI [5.74–5.86]) HIV serology tests were performed (87 per 1,000 inhabitants), a number that has been steadily increasing since 2013 (+11%), while the positivity rate (1.9 per 1,000 tests) decreased (-13%). Nearly 6,200 people (95% CI: [5,897–6,412]) learned of their HIV-positive status, a decrease compared to 2017 (-7%). The serological tests leading to these diagnoses were most often performed in the presence of clinical signs or laboratory findings suggestive of HIV infection (26%), during routine screening (20%), or targeted screening (20%). In 2018, 25% of diagnoses were made at an early stage and 29% at an advanced stage of infection, proportions that have remained stable over the past three years. Diagnoses at an advanced stage were particularly common among people who inject drugs (PWID) (55% of PWID) and heterosexuals (33% of those born in France, 35% of those born abroad). More than half (52%) of those discovering their HIV-positive status had never been tested for HIV before, a higher proportion among IDUs (81%) and people born in sub-Saharan Africa (65%), and a lower proportion (33%) among men who have sex with men (MSM). These proportions have remained stable over the past three years. The decrease in the number of new HIV diagnoses, coupled with an increase in testing activity, may reflect a decrease in the number of undiagnosed infected individuals and/or a decline in incidence over the past several years. Nevertheless, the number of people diagnosed at an advanced stage of infection indicates that efforts to raise awareness about HIV testing must continue.