World No. 1 Serena Williams shook off memories of a first-round loss to France's Virginie Razzano in last year's event by dominating Georgia's Anna Tatishvili 6-0, 6-1 on the red clay at Stade Roland Garros.
She is seeking a fifth crown in five events after titling in Miami, Charleston, Madrid and Rome coming into the French Open.
The 30th-seeded Venus Williams, meanwhile, succumbed to Poland's Urszula Radwanska 7-6 (7-5), 6-7 (4-7), 6-4 in a hotly contested first-round bout. Radwanska prevailed in a 3-hour, 19-minute marathon.
Venus Williams lost in the opening round at Roland Garros for the first time since 2001.
Razzano, Yulia Putintseva, Shelby Rogers, Caroline Garcia, Petra Cetkovska, Donna Vekic, Dinah Pfizenmaier, Galina Voskoboeva and Mallory Burdette also notched first-round triumphs.