In France, carbon monoxide (CO)—an odorless gas produced by the incomplete combustion of carbon-containing materials (gas, coal, wood, fuel oil, etc.)—causes about 100 deaths each year. However, there are regional disparities in the incidence of CO poisoning, with the most densely populated regions being the most affected, such as Nord-Pas-de-Calais, Île-de-France, and Rhône-Alpes. In 2012, more than 1,400 cases of poisoning were reported to the surveillance system, involving nearly 4,460 people. Approximately 84% of those poisoned were treated in a hospital emergency department, nearly 32% required hospitalization, and approximately 20% of them received hyperbaric oxygen therapy. The reported cases of CO poisoning are predominantly accidental domestic poisonings, two-thirds of which occurred in homes. The primary source of these poisonings is an appliance connected to an individual flue and fueled by mains gas (boiler, water heater, etc.). Among non-connected appliances, the most common are fire pits/barbecues, portable space heaters, generators, and construction equipment. Among connected installations, poisonings most often occur due to a defect in the exhaust flue, inadequate ventilation, or a defect in the appliance itself. For non-connected appliances, the most common issues are misuse of the appliance and inadequate ventilation. However, more than three-quarters of French households with combustion heating appliances are unaware that they have devices in their homes capable of emitting CO, according to the Environmental Health Barometer (INPES).