In the international context of efforts to combat the stigmatization of people with mental health problems, representations and attitudes about these illnesses have not to date been widely investigated in France. However, new technologies offer an unprecedented opportunity to collect such information on a large scale and to deploy more efficient action against stigma. The Crazy'App survey was designed as an instrument for studying potentially stigmatizing representations and attitudes towards mental disorders. It asks respondents to react, rather than to standard diagnostic labels or case vignettes, to video testimonies by people with different mental disorders talking about their experiences.