He also won his first Grand Slam at the Australian Open in January, and the Swiss number one admitted that he was still trying to adapt to his new lofty status in the game.
"I was completely flat. I was not really relaxed with my game. I wasn't aggressive. I was playing some bad rallies. Everything was terrible," Wawrinka told reporters.
"I always put a lot of pressure on myself. But before the match and during the match it was not really about only the pressure. I think it's just a different story. Now it's a different picture for my career. I need to put the puzzle back together, but differently than in the past.
"Because now it's after winning grand slam, Masters 1000, being number three in the world. Everything is different, and I still didn't find all the pieces."
The loss means that Wawrinka is the first Australian Open champion to lose in the first round of the French Open since 1998.