Despite a goal from Czech midfielder Tomas Soucek, West Ham's efforts against Stade Rennais were not enough to earn them a pre-season victory.
The French team steamed ahead in the opening ten minutes, when French midfielder Baptiste Santamaria found the back of the net with a long-range strike from 35 yards out.
David Moyes named an almost full-squad for the first time and headed into the second half level with their French opponents.