During the protest, activists could be seen wearing T-shirts that said: "We have 989 days left.”
That’s the number of days activists believe we have to act.
Here is everything you need to know about it.
Protesters from the Derniere Renovation group, who have disrupted other high-profile sporting events, used flares to block the route about 36 kilometres from the finish line.
Stage leader Alberto Bettiol cycled through a cloud of pink flare smoke before being asked to dismount from his bike by a race official shortly before the stage was halted.
Despite the protestors being shackled together around the neck, tour organisers hauled the small group of young activists off the road.
Both the stage breakaway and the peloton were held up until the route was cleared.
“We need to make our government react as they lead us to the slaughterhouse.”
Tour de France organisers, ASO, declined to comment on the protest, but Sir Bradley Wiggins, commentating on the scene from an in-race motorcycle, told Eurosport viewers: “It really was going off. It was quite crazy. A lot of people were getting quite angry, some of the directeur sportifs got out the cars, stuck a boot in.”
The Tour has often been the target of protests, but this year the event organisers pledged their commitment to minimising the race’s carbon footprint.
According to this year’s road book, the manual sent to all race workers, the Tour is “resolutely committed to being an increasingly eco-responsible organisation.”
Who are Derniere Renovation?
Derniere Renovation (Last Renovation) is an activist group focused on raising awareness of the climate crisis.
It describes itself as a civil resistance campaign aimed at achieving a political triumph over energy renovation using nonviolent disruption activities that are repeated over time.
“Our goal is to force legislation to drastically reduce France’s emissions,” it sayson its website, “starting with energy renovation, the area most likely to bring together social and climate justice today.
“Faced with the current ecological disaster, we want to demonstrate that it is possible for citizens around the world to impose on their governments the political agenda that we desperately need.”
It wants the French government to immediately commit to ensuring a total and efficient renovation of French housing stock by 2040, as well as the development of a simple and progressive financing scheme that could help pay for homeowners to make such renovations.
On 3 June, a young woman from the group interrupted the men’s semifinals of the French Open by tying her neck to the tennis court’s net.
Immobilised in front of the crowd and nearly two million people watching on television watchers, she answered to the boos and whistles with a message in English written on her T-shirt: "We have 1,028 days left."
She was taken away after 15 minutes and held in police custody for nearly two full days.