A £35.45 million fine was handed to Guess by EU antitrust regulators after it illegally blocked cross-border sales in to Europe.
The fine was given as part of a crackdown against illegal practices blocking ecommerce in the EU.
The investigation started in June last year after a year-long research into the cross-border online sales practices of almost 2000 retailers.
It was found that the illegal practice continued to occur until October 31, 2017.
Guess’ distribution deals with retailers allegedly restricted the European Commission from using the Guess brand names and trademarks for online search advertising and interfered with setting the retail price.
An authorisation by retailers was also required before being able to sell Guess products online.
They were also prohibited from selling to consumers outside of authorised areas.
Guess’ illegal practice resulted in retail prices increasing five to 10 per cent higher in central and eastern Europe than in western Europe, according to the commission.
Meanwhile, Guess complied with the EU competition enforcer by giving substantial evidence and therefore receiving a 50 per cent cut in the fine.