The GDPR related violations causing a penalty for Google of 50 Million euros are:
1. no transparency and information: the information provided by Google is not easily accessible for users and some information is not always clear nor comprehensive
2. not having a legal basis for ads personalization processing since the consent is not validly obtained as the users’ consent is not sufficiently informed, neither “specific” nor “unambiguous”
Read more about this topic at: https://www.cnil.fr/en/cnils-restricted-committee-imposes-financial-penalty-50-million-euros-against-google-llc