According to the Republic TV news channel, the lawsuit against Google's Alphabet unit claims that it secretly gathered information about people's activities through Google Analytics, Google Ad Manager and other applications and website plug-ins, including apps.
The complaint said that the tech company collected the data to learn about users' friends, hobbies, shopping habits and even the "most intimate and potentially embarrassing things" they search for online.
Jose Castaneda, the Google spokesperson, stated that the company would defend itself against the claims.
"As we clearly state each time you open a new incognito tab, websites might be able to collect information about your browsing activity", Castaneda said, as quoted by the media.
The lawsuit seeks at least $5,000 for each of the millions of users whose privacy has been breached by Google while browsing in private mode since 1 June 2016.