The top-seeded Wawrinka was in control from the outset and secured the win in 65 minutes when the unseeded Paire double-faulted on match point.
"I was playing my best game today," said Wawrinka, who has won all four finals he's appeared in this year. "I was feeling the ball well and playing really aggressively, so I'm very happy with the way I played."
In addition to Roland Garros, Wawrinka has won titles this season at Chennai and Rotterdam. He improved to 5-1 against Paire, who upset local favorite Kei Nishikori in the semifinals.
Paire, who struggled with a sore left ankle, was broken four times and committed 12 unforced errors in the match.
"When I woke up this morning I couldn't walk," Paire said. "One hour before the match it was very painful so I said, 'What can we do?' I spoke with the physiotherapist and we got an anesthesia for my foot. I couldn't feel anything in my foot and it's tough to move when you don't feel your foot."
"It's a big tournament for me," Wawrinka said. "You've had some amazing winners here over the past. I got a lot of support here all this week, and to add this title is very important for me."