This article reports on a method of observing the effects of ethno-racialization of individuals on the way in which they are treated in TV programmes. The first part presents methodological reflection on how the social and sociological requirements of the analysis of television representations of ethno-racial 'diversity'? are taken into account. In the second part, the quantitative measurement of the ways of casting individuals, according to the characters and the social statuses represented, shows that there is a stereotypical disparity in individuals' treatment in programmes, depending on whether they are seen as 'white'? or 'non-white'?. In the last part, explanatory hypotheses are put forward on the logics of discrimination and stereotypization peculiar to the cultural TV industry and its relationship with the imagined audience.