In France, 4.2 million people live in substandard housing, including 350,000 who are homeless. This social issue is compounded by a less visible mental health challenge. Indeed, decent housing plays a protective role, as demonstrated by the “Housing First” program, which is designed for people with mental health disorders and treats housing as a fundamental element of recovery. Today, the “Housing First” public policy targets people in highly precarious situations, based on the premise that having a “home” improves mental health.