We believe privacy and security are fundamental human rights, so we also provide a free version of ProtonVPN to the public. Unlike other free VPNs, there are no catches. We don’t serve ads or secretly sell your browsing history. ProtonVPN Free is subsidized by ProtonVPN paid users. If you would like to support online privacy, please consider upgrading to a paid plan for faster speeds and more features.

Source: ProtonVPN: Secure and Free VPN service for protecting your privacy

Hosted in Switzerland, so privacy invasions are covered by criminal law