Makoun, on loan from English Premier League Aston Villa, scored following an 88th-minute corner as Rennes rescued a point after having twice trailed.
Giovanni Sio put Sochaux, 14th in the table, ahead from close range in the 21st minute only to see centre back John Boye equalise with a header in the 34th.
Sochaux, who beat leaders Paris St Germain 3-2 last weekend, went back ahead thanks to a superb Sebastien Corchia strike in the 56th.
The visitors were then thwarted by several fine saves from Rennes goalkeeper Benoit Costil before Makoun snatched his late goal.
European hopefuls Rennes have 41 points from 26 games, level with fifth-placed St Etienne who visit bottom club Nancy later on Saturday when champions Montpellier also travel to struggling Evian Thonon Gaillard.
On Sunday, former England captain David Beckham could make his debut for PSG against third-placed Olympique Marseille.