The French regulator, CNIL, questions the legality of Worldcoin project's biometric data collection, based on zero-knowledge proofs for identification through retinal scans or phone numbers. Worldcoin claims 2.1 million users have signed up in the last two years. The startup opened registration globally, with founder Sam Altman showcasing a queue in Japan for retina scans in exchange for WLD tokens. CNIL initiated an investigation with German authorities' help, and the UK Information Commissioner's Office will also study the user verification process.