Unlike the rest of France, the police force in Paris runs its own psychiatric unit in which suspects with possible mental health problems or people acting strangely in public can be detained for observation. Up to 2,000 people a year are sent there. Campaigners have long tried to get the establishment closed down, and the inspector general of prisons has himself condemned its blurred role between mental health care and public order. But both the head of the police in Paris and City Hall have so far succeeded in resisting attempts to shut it. Lousie Fessard reports.