Lille have 73 points with one match left and enjoy an unassailable six-point lead over second-placed Olympique Marseille, who also drew 2-2 at home to strugglers Valenciennes.
"I'm going to thank our fans because they have been great throughout the season. We wanted to do it tonight, we did it," coach Rudi Garcia, whose team beat PSG in the cup final on May 14, told French TV channel Canal Plus.
"They're a fantastic squad and someone has to tell them because they don't realise what they just did.
"When they will see each other in 15 or 20 years, they will have fantastic memories to share."
Lille, who notably beat defending champions Marseille 2-1 away in March, took control of the league in early December and surrendered top spot just once since in a season fans could only have dreamed about given the club's limited means.
The weekend could get even better for club president Michel Seydoux, a film producer who could be awarded the Palme d'Or at the Cannes festival for 'Pater'.
"Champions always look good because they are the most regular through the season," OM coach Didier Deschamps told Canal Plus.
"Congratulations to Lille, their players, their coach, their staff. Bravo."
Marseille are now certain to finish in second place and play in the Champions League next season with third-placed Olympique Lyon poised to grab a spot in the competition's third qualifying round.
Hoarau was sent off early in the second half for a second bookable offence and was soon followed by coach Antoine Kombouare, who had a spat with the officials and Lille's assistant coach.
Lille then went ahead on 59 minutes as Moussa Sow, the league's top stri
