Lyon were 2-0 up at half-time and cruising to victory at struggling Nice but the two dropped points meant they stayed in fourth spot rather than jumping up to third in Ligue 1 following Stade Rennes' 0-0 draw with Auxerre on Saturday.
Claude Puel's Lyon are now eight points adrift of leaders Lille, who beat Caen 3-1 on Saturday, and four behind champions Marseille with nine games left.
"It's difficult but it's not over," Puel told a news conference when asked if Lyon's chances of regaining the title they won seven times in a row between 2002 and 2008 had gone.
"We've got to bounce back and better control the end of our matches for the season's climax," he added.
Renato Civelli netted Nice's equaliser three minutes into added time following a corner after Eric Mouloungui had made it 2-1 moments earlier from the penalty spot following a foul by Pape Diakhate, who was sent off for two cautions.
Diakhate had earlier conceded another spot-kick on 50 minutes but Danijel Ljuboja's effort was saved by France goalkeeper Hugo Lloris.
Sweden's Kim Kallstrom opened the scoring for Lyon with a free-kick on 22 minutes as they dominated the first half and Argentine striker Lisandro Lopez doubled their advantage just before the break with a cool finish after Nice lost possession.
Champions Marseille won 1-0 at second-bottom Lens thanks to Benoit Cheyrou's 69th-minute curling strike after the midfielder showed excellent trickery on the edge of the box.
Lens hit the bar in the first half and forced Steve Mandanda into two superb saves.
In Sunday's other game, Saint Etienne did little to boost their hopes of a Europa League berth with a 1-1 draw at home to relegation-threatened Valenciennes.
