© AP Photos
The home side made a bright start to the match, but it was Lyon who made the early breakthrough, Gueida Fofana curling the ball into the bottom corner of the net.
Bafetimbi Gomis, who was a late addition to the side, was a handful early on, forcing two quick-fire saves from the hosts before sending the ball inches wide.
The striker got his reward in the 26th minute when Alexandre Lacazette beat the Valenciennes defence to get a cross to Gomis, who smashed the ball in from close range.
Gomis continued to look threatening throughout the second half, but Lyon was content to ease off as full time drew nearer, happily protecting their two-goal advantage.
The win puts Lyon back at the top of the Ligue 1 table, while Valenciennes jump a place to 11th.