From gdpr.eu:

"The more serious infringements go against the very principles of the right to privacy and the right to be forgotten that are at the heart of the GDPR. These types of infringements could result in a fine of up to €20 million, or 4% of the firm’s worldwide annual revenue from the preceding financial year, whichever amount is higher."

For Google that would be 4% of its worldwide annual revenue, I'd assume. Taking into account that it's not one infringement but multiple that could mean a pretty hefty fine.