Montpellier, who along with pundits never considered themselves title contenders before the season, are on 69 points with five games to play while PSG entertain strugglers Sochaux on Sunday.
Camara was lucky to score after five minutes when a Younes Belhanda cross bounced off his knee before hitting the post to go into the net.
Montpellier, whose attacking flair has stunned French football this term after they finished 14th last season, focused on their defensive effort for once after they were beaten at relegation-threatened Lorient last weekend.
The Ligue 1 leaders had few chances against Valenciennes, though they were denied a penalty when Nicolas Isimat-Marin handled a John Utaka volley.
"We needed to reassure ourselves at home and we did," playmaker Belhanda told Foot+ television.
"We will watch Paris' match tomorrow, but we are more focused on ourselves and the league matches to come."
Eden Hazard, being watched by a host top European clubs, set up a goal and scored the second in the first half to earn third-placed
Champions Lille were down to 10 men after just 36 minutes. Captain Rio Mavuba fired into the top corner from a Hazard pass in the 39th minute, then the Belgian bent the ball past keeper Baptiste Reynet from close range in first-half stoppage time to seal the victory.
Lille occupy the Champions League play-off round berth with 62 points, eight ahead of
Brazilian playmaker Jussie put the hosts ahead in the first minute from a Yoan Gouffran pass and then unleashed a powerful shot to double the lead midway through the half.
Jordan Ayew volleyed home from a corner kick in the 57th minute for the visitors, whose keeper Steve Mandanda saved a Benoit Tremoulinas penalty midway through the second half.