Between April 10 and 18, 2019, Santé publique France received 7 reports of pediatric hemolytic uremic syndrome (HUS) from hospital departments participating in the surveillance program, compared to fewer than 10 cases reported per month in April in previous years. Epidemiological investigations began on April 18 using the standardized STEC questionnaire to identify common exposures among the cases. Stool samples were sent to the laboratory associated with the National Reference Center (LA-RD) for confirmation of infection with Shiga toxin-producing Escherichia coli (STEC), and sequencing of the isolated strains was performed by the National Reference Center for E. coli, Shigella, and Salmonella (CNR-ESS). Starting on April 26, an upstream and downstream traceability investigation of the suspected food products was conducted by the Departmental Directorate for Population Protection (DDPP) and the General Directorate for Food (DGAl), in collaboration with the national headquarters of the retail chains involved in the sale of these products. Microbiological analyses of food and environmental samples at the producer’s facility were conducted by the National Reference Laboratory for E. coli (LNR). A case was defined as a person who, between March 1 and May 12, 2019, presented with diarrhea or HUS with detection of the epidemic STEC strain (confirmed case) or, with an epidemiological link and no detection of the STEC strain (probable case). A total of 19 cases were identified in connection with this outbreak (18 confirmed cases and 1 probable case), including 17 cases of HUS and two cases of uncomplicated diarrhea (one child and one adult). The median age of the cases was 22 months (range: 6 months–63 years). Fifty-three percent of the cases were female. Among the 17 children who developed HUS, 8 (47%) had neurological involvement. The cases resided in 8 regions of metropolitan France and developed symptoms between March 31 and May 12, 2019. In 18 cases, a strain of STEC O26 carrying the stx2 and eae genes was isolated (STEC analysis was negative for one case). Phylogenetic analysis conducted by the CNR-ESS showed that the 18 strains belonged to the same genomic cluster (cgMLST HC5|75047 and SNP analysis). Consumption of Saint-Félicien and/or Saint-Marcellin cheeses was reported for 15 of the 18 confirmed cases, either by the patient (11 cases) or by family members (4 cases). Purchase traceability identified a possible link to a common producer of these cheeses in the Drôme (department 26). The purchase of cheeses from this producer was documented on the loyalty cards of 7 cases. For the other cases, the places of purchase cited by the families were supplied by the implicated producer during the relevant purchase period. Food samples (from cheeses collected before and after the outbreak period) and environmental samples taken at the producer’s facility tested negative. The cheeses were distributed abroad, but no other cases outside France have been identified in connection with this outbreak. Withdrawal and recall measures were implemented as of April 27, without waiting for the results of human strain sequencing and microbiological investigations at the producer’s facility. Indeed, this decision was based on the information available as of April 27: the high number of pediatric HUS cases (19 suspected cases under investigation), the predominance of serogroup O26, the high frequency of consumption of Saint-Félicien and/or Saint-Marcellin cheeses reported among the cases, and the identification, via loyalty cards from the same producer, of cheeses purchased by several families of the cases. This outbreak once again highlights the risk posed by the consumption of raw-milk cheeses for vulnerable populations, particularly young children. Following this outbreak, the DGAL, the DGS, and Santé publique France have strengthened their prevention messages to consumers.