On 28 June, the heir to the Austro-Hungarian empire was assassinated in Sarajevo. By co-incidence, one of the royal chauffeurs was former Mercedes works-driver Otto Merz. A week later, the French Grand Prix was held under an increasingly tense political situation across Europe. The city of Lyon promised large subsidies and the race was held on a 38 km road circuit to the south of the city. It ran from Les Ronzières to Givors, then along the bank of the Gier (a tributary of the Rhône) to Châteauneuf before taking an undulating 15km straight back to a steep downhill right-left and a hairpin to complete the lap.