Many poor neighbourhoods, home to both socially disadvantaged populations and to foreigners, are characterised by a strong perception of insecurity. The purpose of this article is determine the origin of this perception. To do so, two possible causes are dissociated: racial prejudice and racial proxy (the ethnic minorities are perceived in terms of the negative social characteristics that are often associated with them). More specifically, it is shown that the ‘ethnic’ variable captures the effects of an overconcentration of poverty, approximated here by the concentration of unemployment, but that these two variables act separately. This result should be taken into account in the policies implemented by public authorities and local actors. In this study, an original methodology is applied based simultaneously on individual geocoded data, the proportion of foreigners, the unemployment rate at the neighbourhood level and an indirect indicator of perceived insecurity.