The Polish star outplayed the unseeded Czech 6-2, 5-7, 6-4 in their women's singles championship match to defend her Paris crown and claim her 14th career singles title.
The 22-year-old dropped only one set on her way to victory.
Świątek also triumphed at Roland Garros last year and in 2020.
In September last year, the Pole won the US Open, capturing her third Grand Slam trophy.
The Polish player, coached by countryman Tomasz Wiktorowski, has topped the Women's Tennis Association's (WTA) world rankings since April 4, 2022.
She now leads the official world rankings with 8,940 points, ahead of Belarusian Aryna Sabalenka with 7,541 points, and American Jessica Pegula with 5,205 points.
(gs)
Source: Eurosport, IAR, PAP, polskieradio24.pl, wtatennis.com