Because it has been used for centuries, lead is now a common industrial toxin and an environmental pollutant. Lead is or has been used in a wide variety of industrial applications and in certain everyday products and items (batteries, electronic components, metal alloys, plastics, glassware, ceramics, ammunition, cosmetics, paints, and inks, etc.). Lead is a cumulative toxin with no known physiological role in humans, and its presence in the body always indicates exposure. Health effects at low levels of exposure are well-documented, and furthermore, lead is a toxin whose effects occur without a threshold. Epidemiological studies have revealed non-threshold associations between blood lead levels and various health effects (cardiovascular, renal, neurotoxic, reproductive toxicity, growth retardation, prematurity, etc.). The population is exposed through food, drinking water, indoor and outdoor dust, soil, and air. The uses of lead are governed by several European directives transposed into French law. Despite regulations on its use, its persistence in the environment, its ubiquitous presence, and its proven toxicity make it a compound that requires continued monitoring. In France, data on lead exposure levels in the general population exist but need to be updated. The National Nutrition and Health Survey (ENNS) estimated lead exposure levels in the general adult population in 2006–2007, and the Saturn-Inf study conducted in 2008–2009 determined the prevalence of lead poisoning in France among children aged 6 months to 6 years. Since then, the cross-sectional Esteban study (Study on Health, Environment, Biomonitoring, Physical Activity, and Nutrition) measured lead exposure levels in the mainland French population aged 6 to 74 years between April 2014 and March 2016. The detection rates were 100% for both children and adults. The geometric means for blood lead levels were 9.9 and 18.5 µg/L in children and adults, respectively. The investigation of exposure determinants confirmed the exposure factors known from the literature. Among children, tap water consumption, the year of construction of the home, and parents’ occupational activity increased lead exposure levels. Among adults, the most significant exposure factors identified were tobacco use, the year the home was built, age, the participant’s place of residence, consumption of tap water, alcoholic beverages, bread, and baked goods, and the consumption of home-raised livestock products. Despite a decrease in blood lead levels in France, risk factors for lead exposure—which are increasingly being studied—persist in the general population. The results of the Esteban study allow us to track changes in lead exposure levels among the French population and to update the list of determinants of this exposure in France for 2014–2016. These results could also be used to inform public health decisions aimed at continuing efforts to reduce exposure.