In a municipality located near the Paris metropolitan area and home to numerous infrastructure facilities (high-voltage power lines, major roadways, industrial sites), local residents have expressed concerns about a potential “cocktail effect” resulting from their combined exposure to these sources of pollution and nuisance. In response, national expert agencies developed maps and measurements of individual exposures to noise, low-frequency electromagnetic fields, and air pollutants, and assessed health concerns using a sociological approach. During public meetings, residents’ knowledge was drawn upon to identify local sources of pollution, sensor locations, and the selection of reference populations. The protocol for the sociological study was co-developed with representatives of local residents. The debates focused primarily on the size of the study population, the indicators selected for noise pollution, and the timing of the measurement campaigns. The study reports were posted online and disseminated via newsletters. At the time, this work helped bring to light the issue of territorial inequalities in exposure within the Île-de-France region; it encouraged the development of more qualitative approaches to describe residents’ perceptions of their environment, health, and quality of life. Some of the issues identified during the Champlan project led to methodological advancements and the development of other forms of participatory mechanisms. While this pilot project lacked coordination with decision-makers, the area studies conducted since 2010 now include in their governance the agencies with the authority to address potential sources of noise and pollution. [authors' abstract]