In August 2009, a nursing home for the elderly (Ehpad) in the Vaucluse department reported seven suspected cases of influenza. Since the nasal swabs taken to test for the new A(H1N1)2009 virus came back negative, heat-related health issues were suspected, and an investigation was conducted. A case was defined as the onset, between August 17 and 24, of a fever with or without respiratory or systemic symptoms. Data were collected from medical records and the medical staff. Among the 78 residents, 7 presented with heat-related conditions. Risk factors for heat-related health issues, as described in the literature, were identified both at the individual level (multiple comorbidities, use of numerous medications, loss of independence) and at the environmental level (urban building, rooms facing southeast and southwest, rooms on the top floor). The investigation showed that, despite the existence of procedures, the management of cases proved inadequate and delayed. Indeed, several warning signs did not trigger a response (complaints from certain patients, hypernatremia, activation of the heatwave alert), and it was a procedure for influenza—not a heatwave—that triggered the alert. Training sessions involving the sharing of experiences between nursing homes and within them are recommended. (R.A.)