Montpellier are eight points behind Lyon in the table but Garde said that they can still qualify for Europe and so will be fighting hard.
"The win in the last game is a boost but we can't rest on those three points," Ligue1.com quotes Garde as saying. "Every game from here on in will be a battle.
"Montpellier has never been a place to pick up easy points. That's the case again this season. They have a quality side and I'm not here to judge their performances.
"I don't know if they still believe in European qualification but games against OL are always tough games with a lot of intensity."
Lyon are 11 points behind leaders Paris Saint-Germain.