The hosts went ahead in the first half thanks to Jonathan Bamba's strike after Rennes defender Sacha Boey's red card. Lille's Reinildo Mandava was then sent off and the visitors levelled after the break courtesy of Damien Da Silva's goal.
Rennes went down 10 when Boey was shown a straight red card for a high foot in the 34th minute, which resulted in the 19-year-old being carried off the pitch on a stretcher after falling heavily on his back.
It was the turning point in a poor first half as Bamba fired home a low cross shot from just inside the box - the first effort on target of the game - to put the hosts ahead five minutes from the break.
Lille also lost a player on the stroke of halftime as Mandava picked up a straight red card for a brutal tackle on Raiphinha.
Rennes, who finished third last season, were the better side in the second half and they were rewarded in the 74th minute when Da Silva latched onto Eduardo Camavinga's headed cross to equalise.