France's data privacy watchdog has fined Google 50 million euros ($57 million), the first penalty for a U.S. tech giant under new European data privacy rules that took effect last year.

The National Data Protection Commission said Monday it fined the U.S. internet giant for "lack of transparency, inadequate information and lack of valid consent" regarding ad personalization for users.

The commission said users were "not sufficiently informed" about what they were agreeing to.

It's the biggest regulatory enforcement action since the European Union's General Data Protection Regulation, or GDPR, came into force in May.

Google said in a statement it's "deeply committed" to transparency and user control as well GDPR consent requirements and is deciding "our next steps."