Human listeriosis is a rare foodborne infection caused by the ingestion of food contaminated with the bacterium Listeria monocytogenes. This bacterium is widespread in the environment and is also responsible for infections in animals (zoonosis). It can contaminate many foods at various stages of production. Although exposure to L. monocytogenes is common throughout life, listeriosis is rare in the general population in France (annual incidence of about 5 cases per million people). It is more common in certain at-risk groups, such as the elderly, pregnant women and their newborns, and immunocompromised individuals. It manifests clinically in various forms: invasive or non-invasive. Invasive forms are dominated by bacteremia, meningeal infections, and maternal-neonatal infections. Other invasive forms are rarer: osteoarticular, vascular, or device-related infections. Non-invasive listeriosis appears to be rare and includes acute febrile gastroenteritis, isolated cutaneous forms, or exceptional ocular forms. Mortality from invasive listeriosis is high, ranging from 20 to 30%. The incidence of invasive listeriosis has declined sharply in France over the past few decades due to overall improvements in food safety and the implementation of control plans in the food industry. The risk of developing listeriosis can be reduced by adhering to good food hygiene practices. (R.A.)