The European Union has hit technology giant Meta with a fine just shy of 800 million euros for what it called “abusive practices” involving its Facebook Marketplace online classified ads business.

The EU’s European Commission issued the fine of  797.72 million euros ($846.13m) on Thursday. It accused Meta, which owns social media platform Facebook, of marketplace practices that give its own ad service an undue advantage over competitors.

The advantage stems from Meta automatically tying its ad service – Facebook Marketplace – to Facebook, creating a “substantial distribution advantage”, according to the commission.

“All Facebook users automatically have access and get regularly exposed to Facebook Marketplace whether they want it or not,” it said.

Additionally, it said Meta imposed unfair conditions on other classified ads service providers who advertised on Facebook and Instagram, enabling it to “use ads-related data generated by other advertisers for the sole benefit of Facebook Marketplace”.

Meta contended it did not “use advertisers’ data for this purpose” and has “built systems and controls to ensure that”.

“It is disappointing that the Commission has chosen to take regulatory action against a free and innovative service built to meet consumer demand,” said Meta, adding it would comply with the commission’s order to end the offending conduct but also appeal.

The fine is the latest in a string of hefty penalties that the commission, which regulates the 27-nation European Union, has imposed against Big Tech companies over their practices in recent years. It ranks among the 10 largest antitrust fines.

The penalty takes into account the “duration and gravity of the infringement”, as well as the turnover of Meta and Facebook Marketplace, said the commission.

Meta’s total revenue last year stood at around 125 billion euros ($133bn).

Meta’s dominant position in the market for personal social networks comes with a special responsibility not to abuse it by restricting competition, according to the EU.