Reims ended Saint-Etienne's Ligue 1 winning streak of four games on Sunday evening.
Les Verts, who would have climbed to fourth in the table with a win, were forced to settle for a point after Gaetan Courtet scored a late equaliser for the relegation battlers.
Pierre-Emerick Aubameyang gave Saint-Etienne the lead after 16 minutes at Stade Auguste Delaune.
The Gabon international slotted home from an acute angle to net his 12th goal of the season.
Aubameyang then wasted a good opportunity to double his side's lead early in the second half and he was punished for his wastefulness 14 minutes from time.
Courtet found space on the edge of the area and unleashed a powerful effort, which flashed past goalkeeper Stephane Ruffier in an instant.
