The European Union has imposed a fine of nearly 800 million euros ($840 million) on Meta for breaching antitrust rules by automatically providing Facebook users access to Facebook Marketplace.

Announced on Thursday, the decision highlights Meta's alleged abuse of its dominant market position by imposing unfair conditions on other online classified ad services.

Margrethe Vestager, EU's competition chief, called Meta's practices illegal and demanded they cease.

Meta plans to appeal, arguing the decision overlooks the dynamics of the European online classified market.

The EU's fine ranks among the top ten largest imposed by the 27-nation bloc and is part of ongoing regulatory scrutiny of Big Tech.

The European Commission detailed that Facebook Marketplace, by being tied to Facebook, gains an unmatched distribution advantage, and claimed Meta exploited ad data from competitors for its own benefit.

In response, Meta argued it has appropriate controls and disputed the commission's conclusions.

This fine follows the commission's investigation launched in June 2021, with formal concerns communicated to Meta in December 2022.

Additionally, the commission recently challenged Meta over its 'pay or consent' model, leading Meta to alter its ad targeting policies under pressure.

This action forms part of the EU's broader efforts to regulate major digital companies, supported by the Digital Services Act and Digital Markets Act, which enforce stringent penalties for antitrust violations.