The objective of this study is to provide a contextualized description of the factors contributing to carbon monoxide (CO) poisoning in the Île-de-France region. It also aims to gather the perspectives of poisoning victims and healthcare professionals on ways to improve prevention efforts. Semi-structured interviews were conducted with victims living in the Île-de-France region (n=17) as well as with healthcare technicians (n=25) responsible for environmental investigations as part of the CO poisoning surveillance system in this region. A typology of poisoning circumstances was established: errors by heating technicians, failure to comply with the requirement for annual maintenance of boilers or exhaust ducts by a professional, lack of knowledge regarding the operating instructions for non-vented appliances, exposure to chimney backdrafts linked to adverse weather conditions, and failure by landlords to meet their obligations regarding housing equipment. Poisonings from braziers/barbecues occurred when these devices were used for cooking or heating. Preventive recommendations addressed the categories of people to be informed (young students in their first rental, women living alone, and populations of African or French Overseas Departmental origin regarding braziers), the media deemed relevant (TV, radio, internet), and the stakeholders capable of relaying information (heating technicians, property owners/landlords). This study demonstrates the complementary nature of quantitative and qualitative methods for better understanding the range of factors contributing to accidental domestic CO poisoning.