BRUSSELS -- The European Commission on Thursday fined US tech giant Meta 797.72 million euros ($837.61 million) for breaching European Union (EU) antitrust rules and abusing its dominant positions in the markets.

"The Commission has fined Meta ... for breaching EU antitrust rules by tying its online classified ads service Facebook Marketplace to its personal social network Facebook and by imposing unfair trading conditions on other online classified ads service providers," the European Commission said in a press release.

Facebook Marketplace is an online platform for classified ads, allowing users to buy and sell goods.

The Commission argued that by linking Facebook Marketplace with its social network, all Facebook users are automatically exposed to Marketplace without a choice. This integration gives Facebook Marketplace a significant distribution advantage, making it difficult for competitors to compete fairly.

It also stated that Meta imposes unfair trading conditions on other online classified ad service providers who advertise on Meta's platforms, including Facebook and Instagram. The practice enables Meta to use ad-related data from other advertisers solely to benefit Facebook Marketplace.

Meta's antitrust case goes back to June 2021, when the Commission began investigating possible related conduct by Facebook. In December 2022, the Commission accused Meta of distorting competition in the online classified ads market, to which Meta responded in June 2023.

Meta responded quickly after the EU's ruling, saying that the Commission's conclusions were based on a "hypothetical potential to harm competition" rather than concrete evidence of damage to competitors or consumers.

The company stated that the decision overlooked the "realities of Europe's thriving online classifieds market" and favored incumbent players.

Meta announced that it will appeal the decision.