The National Federation of Associations for Reception and Social Reintegration (Fnars) and the French Institute for Public Health Surveillance (InVS) conducted a two-part study using an action-research approach to improve understanding of the health status, access to healthcare, and rights of people involved in prostitution. A total of 251 people participated in the health and social services component of the study, conducted within social service facilities, and 78 people participated in the medical component, conducted at Centers for Information, Screening, and Diagnosis of Sexually Transmitted Infections (Ciddist) or Family Planning and Education Centers (CPEF). Two-thirds of those surveyed were women, and three-quarters (78%) were foreign nationals. They exhibited numerous indicators of vulnerability (social environment, housing conditions, residency status, health coverage). More than half of the respondents reported being in fair, poor, or very poor health, a proportion significantly higher than that of the general population. Women exhibited particular vulnerability in gynecological and obstetric health (low rates of cervical cancer screening, low use of oral contraception, and high rates of induced abortions). Transgender individuals were heavily affected by HIV, with a reported prevalence of 44%. The study population, which was vulnerable in terms of mental health, was particularly exposed to physical and psychological violence. Given the specific services utilized, this study is not representative of the entire population of people engaged in prostitution in France. Nevertheless, it allows for the formulation of recommendations regarding prevention and access to rights and healthcare. (R.A.)