A spectator taking a selfie has caused a major crash of riders on the 15th stage of the Tour de France.

The stage was won by Dutchman Wout Poels, who rode to his first career grand tour stage win with victory on the slopes of Mont Blanc.

But Sunday’s stage was marred by the spectator who held out a phone to snap a selfie, and sparked a pile-up that brought down about 20 riders 50 kilometres into the day’s racing.

The fan knocked Sepp Kuss’s handlebars. Kuss went down with team-mate Nathan van Hooydonck, bringing down other riders in the peloton.

“There was a narrowing in the town and a spectator in the road, and I guess he just clipped my handlebars,” said Kuss.

“Luckily I’m OK and hopefully the other guys in the crash are all right. It’s not ideal.

“I think it’s fatigue. It’s been such a hard race and everybody is a bit tired. You lose a bit of alertness and there’s always things out of your control as well.”

The Tour and several teams subsequently warned spectators to be more careful.

“Please pay attention to the riders,” the Tour’s official account tweeted shortly after the incident, posing a slow-motion video of a rider ducking under a spectator’s outstretched arm.

Jumbo-Visma tweeted: “Please be always aware when watching cycling at the side of the road.”

Team Confidis said: “Please be careful. So that the party remains a party for the runners but also for you. You don’t need a cell phone to create mind-blowing memories.”

Ineos Grenadiers said: “If you are spectating at this amazing event, please give the riders room to race.”

Sunday’s incident came two years after one of the Tour de France’s, where a woman holding out a cardboard sign caused a massive pile-up during the first stage of the 2021 race.

German rider Tony Martin collided with the sign and fell off his bicycle, with dozens more riders falling as they rode into him.

The incident made headlines around the world and the woman was eventually fined €1200 ($1350) by a French court.

Elsewhere on Sunday, Tour leader Jonas Vingegaard and close contender Tadej Pogacar came home shoulder to shoulder some six minutes after Poels crossed the lines.

Vingegaard’s advantage in yellow remained at 10 seconds going into Monday’s rest day.

Carlos Rodriguez was just behind to strengthen his hold on third place overall. Australia’s Jai Hindley suffered a second tough day in the mountains and dropped to fifth behind Briton Adam Yates .

For Hindley the race is now about making the podium. He began the stage only one second behind Rodriguez, but is now one minute 17 seconds adrift of the Ineos Grenadiers rider and 6.38 behind Vingegaard.

Poels, riding his 10th Tour de France after being part of four winning teams while with Team Sky and Ineos Grenadiers, delivered a second stage win of this race for Bahrain-Victorious. He dedicated it to Gino Mader, his team-mate who died after a crash at the Tour de Suisse last month.

“I always dreamed to win a stage in the Tour and especially with what has happened in the team in the last few weeks with Gino, all of the emotions come,” the Dutchman said.

-with AAP