Starting on December 24, 2012, the Paris Maternal and Child Health Service (PMI) reported several cases of salmonellosis among children attending four early childhood centers in the 7th arrondissement. Subsequently, the National Reference Center (CNR) for Salmonella noted an increase in salmonellosis cases in Paris in December 2012 and identified, among certain cases, a single strain corresponding to a Crispol profile that had rarely been identified until then: the CT51 profile. Investigations conducted following this report identified 40 cases of salmonellosis, including 30 confirmed cases, 4 probable cases, and 6 possible cases. There were 10 children attending early childhood care facilities and 30 community cases. The outbreak involved two strains of Salmonella: S. Typhimurium CT51 and S. 4,12:i:-, a monophasic variant of the Typhimurium serotype. During telephone interviews with the cases, it emerged that a large majority of them had visited a caterer in the 7th arrondissement of Paris in the days preceding the onset of clinical symptoms. An unannounced inspection by the Paris Departmental Directorate for Population Protection (DDPP 75) revealed numerous operational failures at the establishment, and samples taken on-site allowed for the isolation of the S. Typhimurium CT51 and S.4,12:i:- strains on surfaces and in products sold by the caterer. This investigation highlights the role played by the early observation and reporting by the PMI. This report constituted the “visible” part of a larger-scale outbreak involving both institutional and community cases that occurred simultaneously. (R.A.)