Clifford Chance (CC), Cleary Gottlieb Steen & Hamilton and Allen & Overy (A&O) have advised on Google's record-breaking €4.34bn (£3.9bn) fine from the European Commission for breaching EU antitrust rules.

In its ruling, the EC said Google had imposed illegal restrictions on Android device manufacturers and mobile network operators to cement its dominant position in general internet search, as well as breaching consumer choice rules that gave financial incentives to manufacturers that would pre-install Google Search.

Competing systems from alternative mobile phone providers were also found to have been blocked by Google.

Cleary took the lead role for Google on the case, with a team led out of London and Brussels by competition partners Nicholas Levy and Thomas Graf.

A&O also advised Google, although the firm declined to provide further details of its role.

CC, meanwhile, has been advising Fairsearch, the complainant that first alerted the EC to the competition issues posed by Google. Fairsearch is a group of organisations and businesses that monitor competition and fair business in online and mobile search.

The CC Brussels team was co-led by global antitrust chairman Thomas Vinje and fellow partner Dieter Paemen.

Commenting on the decision, which comes after an investigation that began in 2014, Vinje said: "This is another major achievement for CC's antitrust team. Today's decision means that Google should cease its anti-competitive practices regarding smartphones, but also in other areas – smart TVs in particular – where it is foreclosing competition by using the same practices."

CC and Cleary also advised their respective clients on a record €2.42bn penalty handed to Google last year, after the EC ruled it had unfairly promoted its own comparison shopping service in its search results, while demoting those of its competitors.