Danze diverted in Emmanuel Riviere's soft shot on the stroke of half-time.
Toulouse are on 47 points from 28 games, level with third-placed champions Lille who host neighbours Valenciennes later on Sunday. Rennes dropped to seventh on 44 points.
Edouard Butin and Marvin Martin scored either side of the interval to help hosts Sochaux defeat Nice 2-0 in their relegation clash.
Sochaux went up to 19th on 27 points while Nice stay 18th with the same tally but ahead on goal difference. The pair are two from safety.
Butin volleyed in the opener in first-half stoppage time and Martin added the second when he bent the ball in from outside the box.