The aim of this study is to evaluate hiring discrimination against young people in the Ile-de-France region on three different grounds: the reputation of the area they live in, their gender and their ethnic origin (French or Moroccan). The study is based on experimental testing data using a protocol that allows to examine the cross effects of these three dimensions, which we call "conditional discrimination". We study discrimination in a skilled occupation with a high demand - computer developers with MSclevel qualifications - and where discrimination is a priori very limited. For this occupation, we have constructed 12 fictional profiles of job applicants that are identical in everything except the characteristic we want to test. We examine area-based discrimination by giving these fictional candidates an address in one of three towns in the Val-d'Oise department: Enghien-les-Bains (good reputation), Sarcelles (poor reputation) and Villiers-le-Bel (poor reputation exacerbated by highly-publicised riots in 2007). Between mid-December 2008 and the end of January 2009, we sent 3684 applications in response to 307 job offers. The study consists in a statistical and econometric analysis of the replies to these applications.