Since 1987, Legionnaires' disease surveillance in France has been based on a mandatory reporting system and was strengthened in 1997 by the interactive system for reporting cases of Legionnaires' disease between the National Legionella Reference Center (CNR) and the French Institute for Public Health Surveillance (InVS). The CNR performs initial diagnostics and receives samples for confirmation. It also conducts typing of human and environmental strains. The CNR’s genomic profile database of Legionella strains currently lists more than 600 clinical strains and 2,000 environmental strains. At the European level, France participates in the EWGLI (European Working Group for Legionella Infections) network. This network, which includes 31 countries, reports to the health authorities of the country concerned any case of Legionnaires’ disease occurring in a person who has traveled during the 10 days preceding the onset of the illness, specifying the locations visited. (R.A.).