|© AP Photo/Luca Bruno
Mercedes and Pirelli must answer charges that they breached Formula 1 rules by testing tyres together.
The governing body of motorsport, the International Automobile Federation (FIA), has convened the hearing of its international tribunal. The disciplinary body will meet in Paris on Thursday and Mercedes and Pirelli have been summoned to appear.
The key issue is whether Mercedes gained a competitive advantage from testing tyres with Pirelli in Barcelona from May 15-17.
An FIA inquiry determined "the conditions of this testing may constitute a breach of the applicable FIA rules."
Red Bull and Ferrari had protested the tests.