Nils Politt took the honours after a frantic start allowed a powerful 13-man group to get away and put paid to an anticipated bunch finish at the end of the 159 kilometres 12th stage into Nimes.
The break began to splinter inside the last 50km, with Politt riding clear of Harry Sweeny and Imanol Erviti with 12km to go, soloing to the finish in a stage where the average speed was 47.3kmh.
Britain's Mark Cavendish, who is now one shy of Eddy Merckx's record of 34 stage wins after victory in Valence on Tuesday, led home the main peloton some 16 minutes later, padding his lead in the green jersey by picking up the final three points, while Tadej Pogacar retained yellow.
The Slovenian continues to lead overall by five minutes and 18 seconds from Rigoberto Uran, with Jonas Vingegaard third a further 14 seconds back.
With the Mistral wind gusting, organisers delayed the start in anticipation of the high pace, and the attacks flew at the start.
But once the group containing the likes of Politt, Julian Alaphilippe, Edvald Boasson Hagen, Brent Van Moer and Stefan Beissegger had started to build an advantage, the peloton sat up and let them go.
Politt's victory will have cheered his Bora-Hansgrohe team after their three-time former world champion Peter Sagan was forced to withdraw from the race before the stage start with a knee injury.
"It's a dream to win a stage of the Tour de France," Politt said. "Today we heard Peter had to leave the race with knee problems so that changed our tactics. At the start with the crosswinds it was a big group that got away.
"I felt good in the last few days, I was trying to do my best today but to come away with a victory is unbelievable."
Ireland's Dan Martin, who is targeting a stage win on the mountains in this Tour, finished in 130th spot.
Germany's Politt takes the 12th stage at Nimes
