One day after winning his eighth career stage title, Peter Sagan was disqualified for the 2017 edition of the Tour de France cycle race for controversially elbowing Mark Cavendish and causing a serious crash in the fourth stage sprint finish.

There was some cheer for the local crowds, however, as French racer Arnaud Demare stood out to record his first stage win on Tuesday.

In the 207.5 km ride from Mondorf-les-Bains, Luxembourg, to Vittel, France, as the Briton Cavendish tried to cross the line from the right side with just 100m left, he was elbowed by Sagan ahead of him and hit against metal barriers, reports Xinhua news agency. 

Two racers that followed him had no way of making a quick response, and both fell seriously onto the ground.

Medical staff ran in to give the three a simple medical treatment to help them finish the stage.

The 32-year-old Cavendish withdrew from Tour de France in 2014, when he suffered a collarbone fracture after falling down in the first stage final sprint.

He was taken to hospital for further medical check, and was forced to pull out of this year's tournament after fracturing his right shoulder blade, his team Dimension Data announced late on Tuesday.

"Obviously, I'm massively disappointed to get this news about the fracture," Cavendish said.

"I feel I was in a good position to win, but, to lose that and even having to leave the Tour, a race that I've built my whole career around, is really sad," he added.

Not emphasizing his injury itself, Cavendish just could not figure out the way that Sagan treated him, especially that the two racers got on well.

For Cavendish, a crash is just a crash, but he should not have suffered an elbow from his Slovakian opponent.

"I just want to know about the elbow," the 30-time stage winner said.

Sagan was later disqualified by the race commission for his controversial elbowing.

"We decided to disqualify Peter Sagan from the 2017 Tour de France because he endangered seriously several other riders including Mark Cavendish in the final metres of the sprint which happened in Vittel," president of the race commission Philippe Marien announced.

Yellow jersey owner Geraint Thomas also fell victim to another crash in the chaotic final kilometre as racers fought for a good position ahead of the sprint, but the British came unhurt in the crash.

Leading the stage over 190 km just from the start, Guillaume Van Keirsbulck got reeled by the main pack with 16.5 km remaining, but he was undoubtedly awarded the combative racer of the stage.

With an average speed of 61.76km/h in the last 300m, Demare claimed his maiden victory in Tour de France. After snatching 67 sprint points, he also won the sprinters' green jersey from German racer Marcel Kittel.

American Nathan Brown maintained his polka-dot King of the Mountains jersey. Frenchman Pierre-Roger Latour kept the best young racer honour, and Team Sky still sat atop the overall team standings.

Starting from Vittel, the fifth stage will wind 160.5km until La Planche des belles filles after a 5.9 km-long climb with an average gradient of 8.5 per cent, also a first-category climb.