In May 2014, over the course of a few days, 15 patients were admitted to the emergency department at Valréas Hospital with febrile pneumonia. Most had visited a sheep farm in southern Drôme over the weekend of April 26–27, 2014, during a cultural event. The occurrence of clustered cases of febrile pneumonia three weeks after this event suggested an outbreak of acute Q fever. This hypothesis was biologically confirmed by the National Reference Center (CNR) for Rickettsia in Marseille. The purpose of the epidemiological investigation was to confirm the origin of the outbreak. Potential cases were identified through general practitioners, hospital physicians, and clinical laboratories in northern Vaucluse and southern Drôme. The farms visited during the event were documented, along with the patients’ dietary habits and animal contacts. Forty-six confirmed cases of acute Q fever were identified, with a predominance of women (M/F sex ratio 0.6) and children under 16 years of age (41%). The median age was 34 years. The most common clinical signs were fever, headache, arthralgia, and/or myalgia. More than half of the cases presented with cough and/or an abnormal chest X-ray. Forty-one of the 46 cases had visited the same sheep farm, 23 of whom had visited only that farm. The analytical study confirmed that only the suspected farm emerged as a risk factor for disease occurrence. Veterinary investigations identified active circulation of Coxiella burnetii within this farm. This study illustrates the transmission of Q fever through inhalation of Coxiella burnetii from a contaminated sheep farm, particularly during the lambing season. The potential for acute Q fever to progress to severe forms calls for vigilance, and such exposures could be prevented by restricting public visits to farms that have tested negative.