The European Community Respiratory Health Survey (ECRHS) examines the prevalence and risk factors for asthma and asthma-like symptoms in several regions across various countries, with the aim of determining to what extent differences in the distribution of known or suspected risk factors can explain differences in prevalence. This study extended beyond Europe and was conducted in 55 centers across 23 countries. The strictly standardized protocol consists of two phases: a mail-in questionnaire sent to representative samples of administratively well-defined populations (phase 1) and a detailed questionnaire accompanied by in-depth examinations conducted on a subsample of subjects who responded to the mail-in questionnaire (phase 2). Here we present the prevalence of asthma and asthma-like symptoms, as well as nasal allergies, estimated from phase 1 of the ECRHS study in samples of the general population aged 20 to 44 years in three French regions. The three study areas are the cities of Grenoble and Montpellier, and the 18th arrondissement of Paris.