Salvatore Sirigu also beat Bernard Lama's PSG record of 697 minutes without conceding a goal as he kept a seventh clean sheet in succession in the league.
Lille were unluckily denied a first-half 'goal' and also hit the woodwork as PSG, who have 45 points from 22 games and lead Olympique Lyon on goal difference, struggled throughout.
Carlo Ancelotti's men broke through in the 68th minute when keeper Steve Elana let an Ezequiel Lavezzi cross slip from his hands and the ball went in off Chedjou's chest.
Lille thought they had gone in front after 34 minutes but Nolan Roux was deemed offside even though the striker appeared to be in a non-active position.
PSG striker Zlatan Ibrahimovic benefited from a bad clearance in the opening half and his low shot from just outside the box smashed against Elana's right post.
Thiago Motta was replaced by Marco Verratti 10 minutes into the second half after picking up a suspected thigh injury as PSG continued to toil.
Florent Balmont then found himself in a great position for Lille but his pass to Dimitri Payet was cleared by Sylvain Armand.
While Sirigu looked sharp, parrying Payet's fierce shot from just inside the area, Elana's clumsiness eventually cost his team.
Tulio De Melo's strike against the post in the 83rd minute only served to add to Lille's frustration.
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- Salvatore Sirigu