Background Health impact assessment is a method aimed at identifying the potential health impacts of policies and projects before their implementation and suggesting proposals in order to mitigate negative impacts and enhance positive ones. HIA is growing in France mainly at the local level. The Pays de la Loire Regional Health Agency (PDL-HRA) took an early interest in HIA and supported three experiments proposed by the town councils. An assessment was performed to judge its added value, identify success factors and draw lessons for the development of the practice. Methods An evaluation framework was built based on standards and literature. Using a qualitative multiple case study design, a cross-sectional analysis of the HIAs was carried out in order to compare the implementation process in their respective contexts, the governance arrangements and the changes introduced as a result of the HIA. Evaluation draws upon HIA reports, workshops, field observation and 40 interviews that were analysed with NVivo. Results While the conduct of HIAs is generally in line with standards of practice, the analysis of the relevance of HIA and impact characterization remain insufficiently documented. Implementation and success factors depend on the political context, the culture of institutions, actors and the purpose of HIA. Recommendations have been taken into account and changes are emerging. The stakeholders indicate their interest in HIA insofar as it is a meeting point between the concerns of institutions regarding health equity and democracy and it provides tools for action. Conclusions Although the approach is unanimously valued, it faces time, resource and competition with other activities. The continuation of the approach depends on the HRA policy specifying the aims, resources, fields of application and positioning with regard to the partners.These findings are consistent with other French work and literature data. French experience coulfd benefit from that of other countries.