This document, consisting of three parts, is the French translation of the Apheis report for its third phase. Launched in 1999, the Apheis program aims to provide European decision-makers, health and environmental professionals, and the general public with up-to-date and user-friendly information to help them make informed decisions on the issues they face daily regarding air pollution and its effects on public health. This third report first presents the results of research on the communication strategy for this type of scientific data, with the goal of optimizing its use as a decision-making tool. It then provides a summary of the updated results of the assessment of the short- and long-term health impacts of particulate matter pollution (PM10 and PM2.5) across all 26 European cities participating in the Apheis program. In particular, this new study quantifies the health effects of air pollution in terms of loss of life expectancy. Finally, the results from the 9 cities in the French Air & Health Monitoring Program (Psas-9), which are participating in Apheis, are detailed and placed in their local context in separate chapters. (R.A.)