BRUSSELS (Reuters) - Meta Platforms ( META ) is set to be hit in a few weeks with its first EU antitrust fine for tying classified advertisements service Marketplace with its Facebook social network, people with direct knowledge of the matter said.

The move by the European Commission will come more than a year and a half after it accused the U.S. tech giant of giving its classified ads service Facebook Marketplace an unfair advantage by bundling the two services together.

The EU competition watchdog also said Meta abused its dominance by unilaterally imposing unfair trading conditions on competing online classified ads services that advertise on Facebook or Instagram.

Meta could face a fine of as much as $13.4 billion - or 10% of its 2023 global revenue - although EU sanctions are usually much lower than that cap.

The Commission will likely issue its decision in September or October before EU antitrust chief Margrethe Vestager leaves office in November, although the timing could still slip, the people said.

The Commission declined to comment.

Meta reiterated comments made previously.

"The claims made by the European Commission are without foundation. We continue to work constructively with regulatory authorities to demonstrate that our product innovation is pro-consumer and pro-competitive," Meta spokesperson Matt Pollard said.

The company last year sought to settle the EU investigation by curbing the use of competitors' advertising data for Facebook Marketplace but this concession was rejected by the EU enforcer, other sources told Reuters. A similar offer was accepted by the UK competition regulator.

Separately, Meta was charged by the Commission this month of failing to comply with landmark tech rules because of its newly introduced pay or consent advertising model launched in November.