The 33-year-old who last scored a goal in May made his ninth league appearance of the season on Saturday and helped Pal Dardai's men get a point at the Signal-Iduna-Park.
Kalou's 41st-minute effort cancelled out Jadon Sancho's opener as both teams headed into the break levelled.
Morocco international Achraf Hakimi assisted Sancho to fire the hosts ahead again in the 60th minute but the Ivorian's last-gasp penalty ensured both teams settled for a share of the spoils.
The former Chelsea talisman will hope to maintain his goalscoring form when Hertha Berlin visit Darmstadt 98 for their German Cup game on Wednesday.
They are placed fifth in the Bundesliga table with 16 points from nine games.