Australia’s Caleb Ewan sprinted to his second victory on the Tour de France on Tuesday as Frenchman Julian Alaphilippe kept the overall lead after stage 16, where defending champion Geraint Thomas fell but finished with all the main contenders.

The Lotto Soudal rider beat Italian Elia Viviani and Dutchman Dylan Groenewegen, who took second and third place, respectively at the end of a 177-km ride around Nimes as temperatures reached 40 degrees Celsius. 

Ewan, competing in his first Tour de France, is now the only sprint specialist with two wins this year, having already prevailed on the 11th stage in Toulouse last Wednesday. 

"I knew if I kept persisting I would win and now I've got two wins," said Ewan. 

Defending champion Thomas mis-timed a curb and was left with a gash on his left leg after hitting the tarmac hard. 

After his third fall during this Tour, Team Ineos' sports director Nicolas Portal said Thomas felt fine. 

"He's OK, he needed another bike. All his left side is a bit messed up but nothing serious," he said. 

"We have to refocus after the rest day," added Portal. 

33-year-old Thomas remains 1min 35sec behind Alaphilippe in the overall standings, with the following three riders all within 27 seconds ahead of three challenging days in the Alps. 

As temperatures soared, three-times world champion Peter Sagan said the riders' association (CPA) did nothing to protect them after failing to trigger the "extreme weather protocol."

"The CPA should do something to protect us, that's why we pay them," said Sagan, who leads the points classification. 

Wednesday's 17th stage is a hilly 200-km ride from the Pont du Gard to Gap before the overall contenders battle it out for the title from Thursday to Saturday. 

(With input from AFP and Reuters)