French Republicanism prohibits the creation of American-style affirmative action based on racial and ethnic descent. Nevertheless, France has its own affirmative action programs based on socio-economic indicators in given geographical zones. Over the past ten years, there have also been experimental and informal efforts to diversify selective institutions of higher education. This article assesses, through ethnographic field work and in-depth interviews, one of these programs—the establishing of a classe préparatoire aux grandes écoles in a working-class and heavily immigrant suburb east of Paris. The article reveals that while local underprivileged students who attend the classe préparatoire are most unlikely to wind up in a grande école, they just the same receive essential instruction that readies them for university study. As members of the original teaching team leave and are replaced, however, the future of the prépa's mission is far from certain.