Gicquel, who came through qualifying, stopped Simon 7-6 (7-4), 6-3 with a pair of breaks in each set. Gicquel won two-thirds of the points when serving but the difference was in the second set, when he won half the points off Simon's serve.
Gicquel is one of five French players to advance to the tournament quarterfinals. At least one French player has been in the Open Sud de France finals in 10 of the last 11 years. That includes Gicquel, who was the runner-up in 2006 and '07 and No. 1-seed Richard Gasquet, who won the tournament last year.
Gasquet gained a spot in the quarterfinals with a 6-1, 6-3 win over Paul-Henri Mathieu. Gasquet was 7-for-7 in saving break points and also had four breaks.
Other French players to advance were qualifier Albano Olivetti, who got by Nikolay Davydenko 7-6 (7-5), 6-7 (5-7), 7-5 in 2 1/2 hours; fifth-seeded Gael Monfils, who stopped Joao Sousa 6-3, 6-2; and seventh-seeded Edouard Roger-Vasselin, who was a 6-3, 6-4 winner over Dustin Brown.
Third-seeded Jerzy Janowicz finished the second round with a 7-6 (7-3), 6-3 win over Adrian Mannarino and No. 6-seed Jarkko Nieminen topped Pierre-Hugues Herbert 7-6 (7-5), 7-6 (7-5) but Denis Istomin defeated fourth-seeded Dmitry Tursunov 7-5, 6-4.