The purpose of this document is to outline a general organizational framework for the responses provided by the French Institute for Public Health Surveillance (InVS) to requests regarding environmental health at the local level. This approach, based on the analysis of a range of documents (scientific reports, methodological guides, etc.) and situations encountered by the Institute, has been outlined as a process flexible enough to address all situations encountered and consider all possible responses. As a preamble to the presentation of the approach, the various methods and approaches that may be employed during the process are outlined. (R.A.)