Spain's Garbine Muguruza started the defence of her French Open title by beating 2010 champion Francesca Schiavone 6-2 6-4.
Fourth seed Muguruza went into the match having won only three times on clay this season, but she cruised through the first set.
Italian Schiavone, 36, won three games in a row to lead the second set but Muguruza fought back to win.
Muguruza will face Estonia's Anett Kontaveit in the second round.