The Yamaha rider dominated in scorching temperatures at the Sachsenring with fellow Frenchman Johann Zarco finishing second and Australia’s Jack Miller third.
Quartararo snatched the lead at the first corner away from Francesco Bagnaia, who started in pole position, and never looked back, but later revealed he had suffered with illness all weekend.
“I’m tired, I was sick most of the weekend and was coughing during the race,” he said, “but I am super happy.”
This is his third win this season and Quartararo claimed back-to-back victories having also won the Catalan MotoGP at the start of June.
The Frenchman extended his lead at the top of the overall championships to 34 points over Spanish rider Aleix Espargaro as the Yamaha rider earned the 11th MotoGP victory of his career.
At the halfway point of the season, Quartararo remains on course to win the overall world title for the third straight year.
Bagnaia, who dominated free practice, crashed out with 27 laps to go, when his rear wheel slid out from under him, ending his hopes of winning the overall world title to his obvious fury.
This was the third time the Italian has failed to finish in his last four MotoGP races.
