research

When foreign-born individuals naturalize, they are formally equal to native-born citizens. Yet, research shows that foreign-born citizens continue to differ from the native-born long after naturalization, across multiple dimensions. One dimension has remained, however, overlooked: where they live. This paper provides the first systematic examination of residential segregation among foreign-born citizens in a major European country. Using geocoded voter files covering 45 million French citizens, I apply spatial \(k\)-nearest neighbors methods to estimate individual-level measures of segregation. I document three findings. First, segregation varies in nature across origin groups: EU-born citizens cluster with co-nationals while Sub-Saharan Africans experience diverse multi-ethnic contexts. Second, sorting operates at hyper-local scales: more variation in isolation exists within census tracts than between them. Third, intergenerational assimilation is highly stratified: while children of EU-born citizens achieve near-complete spatial integration, children of MENA- and SSA-born citizens experience persistent segregation. These findings reveal a gap between formal political membership and substantive spatial incorporation.