Simon won the indoor hard-court event in his home nation in 2010, 2013 and 2018. He has not won a tournament since June 2019, but got off to a strong start in Metz by winning 23 of his 31 first-service points (74.2%) and 11 of 18 second-service points (61.1%).
The only seeded player in action Tuesday was Georgia's Nikoloz Basilashvili, the No. 5 seed. He advanced when Belgian qualifier Zizou Bergs - who was leading 6-4, 2-1 - had to retire.
France's Arthur Rinderknech outlasted Spain's Jaume Munar 6-2, 2-6, 7-5. Emil Ruusuvuori of Finland beat the Czech Republic's Jiri Lehecka 6-4, 6-4.
San Diego Open
In a matchup of two American qualifiers, Mitchell Krueger took down Christopher Eubanks 6-4, 6-4 in the first round at San Diego.
Krueger, who will face Australian seventh seed James Duckworth in the second round, won a hefty 34 of his 39 first-service points (87.2%). Eubanks served nine aces and saved five of seven break points but committed four double faults.
Japan's Taro Daniel dispatched American qualifier Emilio Nava 6-4, 6-3. Daniel will draw No. 1 seed Daniel Evans of Great Britain in the next round.
American Denis Kudla also dispatched Spanish wild card Fernando Verdasco 6-3, 6-3, while fifth seed Brandon Nakashima of the US beat countryman Zachary Svajda 7-5, 7-6(5).
