Introduction In the military population, trauma-related nightmares (TRNs) are highly associated with deployments and combat-related events. Trauma-related nightmares are also correlated with severity, treatment resistance, and chronicity of Post-Traumatic Stress Disorder (PTSD). However, to date, no specific measure of TRNs has been validated for use in the French language. This study aimed to translate and culturally adapt the English version of the Trauma-Related Nightmare Survey into French and to evaluate the psychometric properties of the translation on veterans. Materials and Methods After the translation and cultural adaptation process, we evaluated the reliability and validity of the French version of the questionnaire (TRNS-FR) in a population of veterans suffering from PTSD with nightmare complaints (n = 56 patients for test-retest and n = 60 for internal consistency), recruited from five French military hospitals. Results Analyses demonstrated that TRNS-FR has good test-retest reliability (r = 0.59) and good internal consistency with PTSD symptoms, insomnia symptoms, and subjective sleep parameters assessed at home. This questionnaire provides a rapid and comprehensive assessment of sleep disturbance and a specific description of TRNs in the population of veterans with severe PTSD. Our results allowed us to propose a valid and reliable French adaptation of the questionnaire. Conclusion Because sleep disturbances and TRNs require specific therapeutic management, the psychometric qualities of TRNS-FR make it a tool of choice for assessing TRNs in future clinical research settings.