Two outbreaks of trichinosis occurred in France in August and October of 1985 and 1,073 cases in all were identified. In the first outbreak, two localities were involved: the town of Melun and the 14th district of Paris. To determine the origin of the contamination, three case-control studies were carried out: among patients' families, among the populations of these two areas, and among the inmates in the prison of Melun. In the second outbreak, cases again occurred in Paris but in a different district (the 12th), in the city's suburbs, and in other towns scattered throughout France. Although no parasites were found in any of the meat examined in either outbreak, results of the study indicate that infection was due to horsemeat consumption and led to the incrimination of two carcasses, one imported from a slaughterhouse in the United States and the other from West Germany. These findings led the French Ministry of Agriculture to order the inspection for trichinosis of all meat from horses slaughtered both in France and in countries exporting horsemeat to France.