Reigning champion Chris Froome managed to cling on to the yellow jersey after it seemed he had lost it, following a crash that forced him to jog the course. Belgian Thomas de Gendt won the chaotic stage.
In bizarre scenes, the British rider decided to jog part of the final kilometre of the Montpellier to Mont Ventoux hill stage after a three-way collision.
Froome lost his bike when he, Australian Richie Porte and Bauke Mollema of the Netherlands crashed into a motorbike that was held up by fans.
Froome tried to ride on but his bike was broken and he started running up the climb before being given first a neutral bike and then a team bike to finish the stage. Belgian rider Thomas de Gendt won the stage amid the chaos.
Initially it was assumed the incident meant the lead passed to Froome's compatriot Adam Yates, who - equally strangely - collided with a distance marker in stage seven. Froome started the day with a 28-second lead over Yates and now leads by 47 seconds.
The race jury made a decision about an hour after the race. Before the official result was announced, Froome seemed confident, tweeting to say he was "still in the yellow jersey."
Froome's sports director at Sky, Nicolas Portal, explained the crash: "The motorcycle couldn't pass because of thousands of fans. It's not one, two or ten but for 200-metres there were hundreds of fans. It's a behavior.. I don't know how to describe it."
Porte was less diplomatic about the perceived lack of crowd control: "The crowd are in your face the whole time, pushing riders... at the top, that was just crazy,” the Australian rider said.
Froome's main rivals, including Colombian Nairo Quintana, were also held up by the crash as a throng of fans obstructed the road.