Mannarino, who drew the final slot on the 10-match Monday schedule, raced through a 6-2, 6-2 victory over Dmitry Tursunov. Mannarino won nearly three-quarters of the points on serve and didn't lose his serve in the 67-minute match.
He also won more points (26-25) off Tursunov's serve than the Russian managed.
The victory earned him a second-round shot at third-seeded Roger Federer, who, like the tournament's other 15 top seeds, has a first-round bye in Paris.
Nicolas Mahut pounded out 11 aces in a 6-2, 6-3 win over Juan Carlos Ferrero. Mahut did lose serve twice but countered that with five breaks. Also, Philipp Kohlschreiber defeated Mikhail Youzhny 6-4, 6-2 with five breaks in nine receiving games.