Each year, 1,000 reports of households accidentally poisoned by carbon monoxide (CO) are collected through the dedicated epidemiological surveillance system. Half of these households own their homes. While the primary source of poisoning is the furnace, other sources have been steadily increasing in recent years, such as outdoor grills or generators. These findings have raised questions about the financial situation of households affected by poisoning. The French Institute for Public Health Surveillance (InVS) and the National Institute for Prevention and Health Education (Inpes) conducted a study to describe the socioeconomic characteristics of households affected by carbon monoxide poisoning. Questionnaires were administered by telephone to households affected by poisoning between September 1, 2013, and March 31, 2014. Of the 886 households reported to the surveillance system, 507 participated in the study. Specific socioeconomic characteristics were associated with certain sources of poisoning. Poisonings from braziers/barbecues mainly affected renters (50%) living in substandard housing (63%), in a financial situation described as barely adequate or difficult (51%), and speaking an African language at home (69%); 33% were unemployed. Households poisoned by generators were first-time homeowners (53%), with a satisfactory financial situation (69%), and rarely spoke an African language (6%); 9% were unemployed. These results confirm the value of investigating determinants of carbon monoxide poisoning—which are not captured by the surveillance system—through the implementation of ad hoc studies. The distinct socioeconomic characteristics associated with different sources of poisoning have enabled the development of targeted prevention tools.