For the past decade, the French Institute for Public Health Surveillance (InVS) has been actively contributing to the development of methods for assessing the health impacts of public policies. The InVS’s integration into European and international environmental health surveillance (EHS) networks helps harmonize these methods to improve the comparability of results across Europe, both in terms of exposure and health impacts. It facilitates the initiation of European data collection during environmental alerts (e.g., extreme weather events), particularly to assess their health impacts. The value of European and international collaborations in ES is illustrated by a few examples. (R.A.)