The public is witnessing disputes among experts regarding the potential health impacts of electromagnetic waves, particularly those emitted by cell phones and their cell towers. The invisible and intangible nature of these waves likely adds to the concern and fuels unfounded fears, as evidenced by the quote cited above. To address this concern and help the public navigate the scientific debates, public authorities have decided to expand public information through a campaign currently in preparation. As part of the preparation for this campaign, the National Institute for Prevention and Health Education (INPES) conducted a study between April and June 2009 on the knowledge, perceptions, and behaviors of the French public regarding the risks associated with electromagnetic waves, particularly those emitted by mobile phones. [author’s summary]