Do integration policies that require migrants to demonstrate allegiance lead to greater or lesser integration into the host society? This paper analyses the effects of a symbolic change in birthright citizenship rules in France on the integration of second-generation immigrants. It exploits an exogenous reform that required second-generation immigrants to formally declare their willingness to become French as a condition for naturalisation.

Using a Difference-in-Differences approach, the findings reveal that, contrary to its stated aim of fostering a greater sense of belonging, this policy led to a decline in national identity and an increase in perceived discrimination among the affected group. These effects are not driven by changes in naturalisation rates or increased hostility. While the reform did not impact economic or political integration, it did weaken cultural integration.

Overall, rather than fostering integration, such migration policies risk triggering a backlash.