This book questions the reality of a crisis of immigrant integration and citizenship in Europe, a crisis that has gained a huge attention in the public and political debates since the 2000s. More often than not, this crisis has systematically been described as the crisis of historical national models of citizenship - e.g. French republicanism, Dutch and British multiculturalism. This book claims, however, that this crisis has never happened for the simple reason that these models have never existed. Understanding the discurse of this "crisis" therefore implies we better understand why we have long believed in the existence of total, coherent, and stable "models" for defining one nation's self-identity. When the politics of the "crisis of integration" emphasize the role of national identity as a solution to integration issues, this leads to a major ambiguity: neither do we know to define our identities nor how our identities define ourselves. Published in Portuguese.