Between 2017 and 2021, 627 incarcerated individuals died by suicide (including 598 prisoners, 95.5% of whom were men). The annual suicide rate was 17 per 10,000 people among men and 23 per 10,000 people among women. For the same age group, it was 10 times higher for men and 40 times higher for women in prison than in the general population. A psychiatric disorder was reported during incarceration in 64% of suicide cases. Among those affected, nearly one-third had no known psychiatric history prior to incarceration. Suicide was preceded by one or more suicide attempts in 46% of cases, either before or during incarceration. In the week preceding the suicide, a significant event—most often of a criminal, prison-related, or family nature—was identified in 61% of cases, and 60% had sought care at the health unit. At the time of the suicide, a suicide risk had been identified by prison authorities in 44% of cases. The suicide rate is six times higher during the first week of incarceration, twice as high during pretrial detention, and 14% of suicides occurred in disciplinary units. Santé publique France considers the suicide mortality rate among inmates to be a matter of concern and emphasizes the importance of strengthening the implementation of suicide prevention measures in prisons.