A psychiatric service near Paris has opened two mobile units with the help and the support of local governments. The authors review their first year's activities involving preliminary consultation with patients without, in the first instance, prescribing treatment or giving any formal diagnosis. The team's action is resolutely preventive. The care of people at risk before they become really mentally ill. Psychiatry is brought from behind the closed doors of institutions to seek the cooperation of social workers and others in bringing about a better understanding of mental illnesses in local communities.