In May 2007, a cluster of Q fever cases was reported among employees at an agricultural training facility in Florac (Lozère). An investigation was conducted to determine the extent of the outbreak and identify the source of exposure. Following an active case search in the municipality where the facility is located, a cross-sectional survey including a seroprevalence study was conducted among individuals who had visited the facility and those living or working nearby between April 1 and May 20, 2007. A case was defined as a person with a positive serological diagnosis of Q fever. Concurrently, a veterinary investigation was conducted to identify animal foci of Q fever in livestock farms on the outskirts of Florac. Of the 128 people surveyed, 14 cases of acute infection were confirmed, including cases outside the training center. Statistical analysis highlights an increased risk of Q fever when participating in outdoor sports and for those living near a manure storage area. The veterinary investigation identified two farms with high Q fever shedding within a 5-km radius of Florac. The results of the investigations suggest airborne transmission from a farm located northwest of Florac. (R.A.)