Google is taking on European Union over antitrust fines at Europe’s second-highest court in a landmark case that would determine how EU enforcers treat the US tech giant over issues of abuse of market power.

The company will lay out its arguments against a 2.4-billion euro ($2.6 billion) fine handed out by the European Commission during a three-day hearing at the General Court.

The EU has fined Google a total of 8.25 billion euros in three separate cases, including one involving its Android smartphone operating system and Google’s favouring its own price comparison shopping service to the disadvantage of smaller European rivals.

Google is expected to launch a three-pronged attack against the commission’s 2017 decision, which also included an order to treat competitors equally.

“It is wrong on the law, the facts, and the economics. Shopping ads have always helped people find the products they are looking for quickly and easily, and helped merchants to reach potential customers,” Google said in a statement.