Image 1 of 5 Peter Sagan (Bora-Hansgrohe) in the green jersey at the Tour de France (Image credit: Bettini Photo) Image 2 of 5 Peter Sagan (Bora-hansgrohe) in the green jersey at the Tour de France (Image credit: Bettini Photo) Image 3 of 5 Peter Sagan (Bora-Hansgrohe) greets the fans at the stage start (Image credit: Bettini Photo) Image 4 of 5 Peter Sagan (Bora-Hansgrohe) before the start of stage 14 (Image credit: Bettini Photo) Image 5 of 5 Caleb Ewan (Lotto Soudal) wins stage 16 (Image credit: Bettini Photo)

Stage 16 of the Tour de France was raced in searing heat in the southern city of Nimes, and Peter Sagan (Bora-Hansgrohe) called for action from the CPA, the riders' association, with the European heatwave set to continue this week.

Temperatures topped 40 degrees Celsius on Nimes on Tuesday, complicating the flat 177km stage. Riders shoved ice in their helmets and jerseys as the peloton battled to regulate their body temperatures.

Sagan finished fourth in the bunch sprint finish and spoke in the mixed zone with the green jersey on his shoulders.

"I had one full bottle, and another, and another, and another. It was crazy," he said.

Sagan went on to suggest he and his fellow riders cannot continue to compete in such conditions, and he even appeared to criticise the CPA.

He pointed out that the flat nature of the parcours allowed for higher speeds and more of a breeze, but warned that it wouldn't be sustainable when climbing mountains in the Alps from Thursday. Temperatures in the Alps are set to be slightly lower than Nimes but still well into the 30s as the heatwave continues until the end of the week.

"It was OK because it was a flat stage, but if we are going to the mountains with this weather, it's going to be very bad," Sagan said.

"I think CPA should do something. I don't know why we pay them when they don't protect us."

Sagan was unable to win the sprint in Nimes but placed fourth to make the green jersey even more secure on his shoulders. He tried to latch onto the lead-out train of Elia Viviani (Deceuninck-QuickStep) but was unable to match the pace of the pure sprinters as Caleb Ewan (Lotto Soudal) won ahead of Viviani and Dylan Groenewegen (Jumbo-Visma).

"Daniel [Oss] and [Marcus] Burghardt kept me out of trouble, and I was in the best position, behind Elia," Sagan explained.

"I was waiting for him to start because it was a headwind. I started too late because Caleb and Dylan came past me pretty fast. I just stayed on the wheel of Elia, and I was a little bit between them and it was hard to pass them."