Following the Paris terror attacks in November 2015, a large number of first responders (FR) were mobilized and consequently were at risk of developing posttraumatic stress disorder (PTSD). Based on the ESPA 13 November survey, the objectives of this study were to 1) describe the prevalence of PTSD and partial PTSD in FR five years after the attacks, 2) describe the changes in PTSD and partial PTSD from one to five years after the attacks, and 3) examine factors associated with PTSD and partial PTSD five years after the attacks. Data were collected using an online questionnaire. PTSD and partial PTSD were measured using the Post-Traumatic Stress Disorder Checklist based on the DSM-5 (PCL-5). Gender, age, responder category, education level, exposure, mental health history, history of traumatic events, training, social support, concern about the COVID-19 epidemic, and somatic problems present after the attacks were all analyzed as potential factors associated with PTSD and partial PTSD using multinomial logistic regression. A total of 428 FR were included 5 years after the attacks, of which 258 had participated also 1 year after the attacks. Five years after the attacks, the prevalence of PTSD and partial PTSD were 8.6% and 22%, respectively. Presence of somatic problems after the attacks were associated with PTSD. Involvement in dangerous crime scenes was associated with a higher risk of partial PTSD. No awareness of psychological risks in the context of professional activity through specific training was associated with partial PTSD, in particular among participants aged 45 years or more. To mitigate PTSD for FR, monitoring mental health symptoms, providing mental health education, and providing treatment may be needed for several years after the attacks.< Réduire