||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. Objectives 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. Methods The web survey was made available on smartphone or computer and advertised on various media and during a French exhibition about mental disorders, mental health and well-being (“Mental Désordre”, Cité des sciences, Paris, 2016). It consisted of short (<2min) video testimonials by four people presenting respectively anorexia, bipolar disorder, obsessive-compulsive disorder and addiction to alcohol. Each testimony was immediately followed by series of questions to which participants were to respond using visual analog scales. The questionnaires investigated different domains, such as the causes of each of these mental disorders, the possible treatments and the respondent's personal attitudes in hypothetical situations (e.g. working with the person seen in the video). After having completed the survey, respondents were offered an opportunity to compare their own responses to those of the other respondents, and watch expert psychiatrists interviews delivering clinical and scientific knowledge and sharing their own attitudes. Results The respondents (n=2600) were young, mostly women, educated and concerned about the subject. They exhibited good knowledge of the disorders. They reported a multi-causal view of the etiologies, where psychological causes were rated higher than neurobiological causes (although less so for respondents reporting having had a mental disorder themselves), while other types of causes (environmental, spiritual, and nutritional) received much lower ratings. Respondents also expressed high potential social proximity, but this result varied according to the type of disorder, in particular, the social distance and the perception of dangerousness were greater for addiction and bipolar disorder. Conclusions Crazy’App operationalizes emerging strategies in the efforts to combat stigma, implementing what is known as a “contact based intervention” in English-speaking countries. While it does not erase the differences in attitudes observed from one pathology to another, this type of survey-intervention based on video testimonies could help to reduce the desire for social distancing from people with mental disorders, even in a particularly sensitized and informed population. Multimedia technologies are an efficient way to offer rich, potentially interactive content better able to embody people and their actual experiences than clinical descriptions or even life narratives. However the use of videos could put the focus on the individual characteristics (physical, gestural, verbal, nonverbal…), and this should be cautiously taken into account according to the anti-stigma objectives. Connected technologies also make it possible to enhance the more classic de-stigmatization actions focused on the deconstruction of preconceived ideas, making the action more participatory, while simultaneously assessing their efficacy. By mediating contact with individuals and behaviors perceived as deviant, the aim would be to develop psycho-social skills and concrete abilities for action in the general population, to include people with mental disorders in the community.