After the devastation of the First World War, France welcomed immigrants on an unprecedented scale. To manage these new residents, the French government devised Europe's first guest worker program, then encouraged family settlements and finally cracked down on all foreigners on the eve of the Second World War. Despite France's famous doctrine of universal rights, these policies were egalitarian only in theory, not in reality. Mary Dewhurst Lewis uncovers the French Republic's hidden history of inequality as she reconstructs the life stories of immigrants--from their extraordinary successes to their sometimes heartbreaking failures as they attempted to secure basic rights. Situating migrants' lives within dramatic reversals in the economy, politics, and international affairs, Lewis shows how factors large and small combined to shape immigrant rights. At once an arresting account of European social and political unrest in the 1920s and 1930s and an exposé of the origins of France's enduring conflicts over immigration, The Boundaries of the Republic is an important reflection on both the power and the fragility of rights in democratic societies.