By the 2008/09 school year the federal state of North Rhine-Westphalia (Germany) abolished binding school catchment areas in all municipalities. The reform has been controversial and it was feared that school choice would increase ethnic segregation. Using data on all primary schools we contribute to this debate by analyzing ethnic segregation before and after the reform. We discuss drawbacks of commonly used segregation indices and their interpretation as well as causality issues. Although there is an increase in segregation over the time period studied, our results show that segregation has not been affected by the policy reform.