Organised by the Berlin-based NGO Civil Liberties Union for Europe (Liberties), the campaign saw complaints lodged in nine member states a week ago. In Slovenia, the Peace Institute addressed the complaint to the Information Commissioner.

The complaints are a means to have the relevant authorities open investigations into behavioural advertising that sees real-time bidding systems share personal data about users with hundreds if not thousands of companies, the Peace Institute said in a press release on Tuesday.

"Every time a person visits a website and they see a targetted ad, their personal data, like browsing history or location, or even sexual orientation, ethnicity, political believes etc. are shared with thousands of companies in real time," Liberties legal expert Eva Simon illustrated.

She underlined that this was a violation of the EU's General Data Protection Regulation (GDPR), adding that the users are powerless against such collecting and selling of their personal data.

Alongside the organised lodging of complaints by NGOs, the #StopSpyingOnUs campaign wants to encourage individuals to lodge their own complaints as well.