This paper tests an empirical implication of Melitz (2003) in the context of falling trade costs, using the EU's intensive liberalization phase (1993−2002) as a natural experiment. Contrary to the model's predictions, firms that switch from non-exporting to exporting over the studied period are not concentrated in a particular size range. Our findings, based on a rich data set of French manufacturing enterprises, suggest scope for fine-tuning of the theoretical framework.