How do the 60,000 people imprisoned in France experience their sexuality? If it seems unthinkable today not to care for and feed prisoners, it will no doubt appear incomprehensible that the prison of the 21st century has not been able to integrate respect for the right to privacy as an essential element of human dignity. . The deprivation and control of sexual relations in prison represent an additional penalty for prisoners and their relatives who experience all the injustice. An ambitious study was needed to overcome stereotypes, particularly with regard to prostitution, rape or homosexuality within the walls. In prison, the regression towards a solitary sexuality drenched in pornography is difficult to avoid. Conjugal sexuality is furtive and humiliating, stolen from the eyes of the guards. A general situation in contradiction with the stated ambitions of the State in terms of reintegration and the fight against recidivism. This unpublished sociological document is also a fascinating human investigation. Sixty men and women detained in France were met on a regular basis. Testimonies have been collected in several foreign countries. The author was also able to question the staff of the prison and medico-social administration. He then questions the nature and use of confinement to put them into perspective with a justice that is too often misunderstood.