Thousands of emergency responders and law enforcement officers were mobilized following the attacks of November 13, 2015, in Paris and Saint-Denis. To assess the psychological impact of these events, as well as the use of healthcare services and support systems, the Post-Attack Public Health Survey of November 13 (ESPA 13-Novembre) was conducted among these responders. This article presents the sociodemographic characteristics of this population, the prevalence of post-traumatic stress disorder (PTSD), and describes the vulnerability factors for PTSD. The survey took place from July to November 2016. To publicize the survey, a media campaign and outreach efforts, disseminated through each participating institution, were conducted. Eligible volunteers for the survey were aged 16 or older and had been involved in response efforts related to the attacks on the night of November 13 or in the three weeks that followed. Sociodemographic characteristics, psychological history, intervention conditions, preparedness for traumatic events, social support, and current psychological status were collected using a secure online questionnaire. PTSD was measured using the PCL-5 (Post-Traumatic Stress Disorder Checklist Scale, DSM-5 version). In total, of the 837 people who began responding to the survey, 698 completed the questionnaire: 34% were healthcare professionals, 30% were Paris firefighters, 20% were civil protection volunteers, 14% were law enforcement officers, and 2% were municipal employees of Paris or Saint-Denis. The prevalence of PTSD ranged from 3.5% to 9.9% depending on the type of responder. The intensity of exposure, lack of preparation for traumatic events, and social isolation were associated with PTSD. These exploratory results suggest the importance of social support as well as preparation for stress management and the consequences of psychological trauma. Further analyses are currently being conducted to confirm these initial findings.