Luxembourg - Facebook's parent company Meta suffered a defeat at the European Union's highest court over data privacy regulations on Tuesday.

National authorities, examining competition cases, may also check compliance with EU data privacy regulations, a press release from the European Court of Justice (ECJ) said.

The case focused on Meta collecting Facebook users' activity data, on and off the social media platform, as well as other Meta services like WhatsApp, for targeted advertising purposes.

Germany's competition authority, the German Federal Cartel Office, banned Meta from data collection without Facebook users' consent, out of concern Facebook was abusing its market position.

Meta challenged the prohibition at a court in Düsseldorf which referred the case to the ECJ.

The ruling from the Luxembourg-based court found that the German Federal Cartel Office did have the authority to impose the ban on Meta's data collection.

When investigating a company's abuse of market dominance, regulations outside of competition law may also be used such as data privacy, the ECJ said.

In this case, the dominant market position of Meta in German's social media market was considered when examining whether the consent to data collection was voluntarily given.

The case returns to the Düsseldorf court to carry out the ECJ's ruling.