Brecht Dejaegere was given a red card in the closing stages of the first half, as Gent face an uphill battle with Lyon at half time.
The midfielder was the Belgian side's most lively player in the first half but was sent off for a one-footed challenge on midfielder Maxime Gonalons.
Alexandre Lacazette caused the home side a few problems and was denied a penalty shout when the Frenchman dribbled in and out of defenders before stumbling over, with the official waving away any claims.
However, it was Gent that had the better chances, as Laurent Depoitre found himself one on one with Anthony Lopes but the attacker's effort was directed onto the bar by the on-rushing goalkeeper.
Gent also had a goal ruled out for offside as it was Depoitre again who was the man involved, after an inch-perfect cross found the Belgian forward inside the box only for the linesman to raise his flag.
