Through the exploitation of geographic variation in the concentration of national and ethnic minorities across France, strong associations were found between increasing population heterogeneity and the functioning of the local criminal justice system. In recent years, worsening economic conditions have led to growing tensions between native-born French and a rising tide of immigrants, largely from North Africa and other parts of the developing world. The French criminal justice system has responded to perceived levels of social disorder and delinquency in these ethnic neighborhoods by increasing police surveillance, widening court jurisdiction, and imposing harsher penalties for offenders. As a result, France’s foreign and immigrant residents, who comprise only about 6 percent of the population overall, now represent nearly 30 percent of the French prison population. In the research world, little attention has been given to the broader social and political context in which crime control strategies are developed. A comparative analysis is conducted of punishment regimes across local jurisdictions in order to assess the relationship between concentrations of national minorities and the institutional response to crime. Tables, notes, and references