The 21-year-old has been unstoppable since February and has now matched Venus Williams' streak of 35 straight match-wins, which is the longest unbeaten run in women's tennis this century.
She is also just the 10th woman to win multiple Roland-Garros titles in the Open Era.
Swiatek started strong, going up a double-break 4-0 in under 20 minutes. Gauff avoided the bagel, holding serve in game five but the set was over on the 34-minute mark as the Pole claimed a third break to take a commanding lead.
A couple of uncharacteristic backhand errors from Swiatek in the first game of the second set gave Gauff an opening and the 18-year-old got her first break of serve of the match when her opponent sent an inside-out forehand wide.
The No.18 seed managed to consolidate for 2-0 but Swiatek retaliated and they were soon on level terms.