'Django Unchained' Actress -- We Got the Pictures ... And It Looks Like Sex

The "Django Unchained" actress who cried racism against the LAPD ... claiming they harassed and hurt her because she was just making out with her white boyfriend in a car -- has some explaining to do, because we obtained pictures that seem to show A LOT more than sucking face.

The pictures were taken Thursday outside the CBS lot in Studio City. You see Daniele Watts straddling BF Brian -- their hands steadying themselves around the sunroof.

An eyewitness who saw Daniele and Brian as he worked in a nearby office tells TMZ ... Brian was sitting in the passenger seat with his feet on the curb and Daniele was straddling him with her shirt pulled up -- breasts exposed. The eyewitness says she was grinding on top of him, rocking back and forth.

Someone from the office went down and asked Daniele and Brian to stop because everyone in the office could see them but they continued.

The eyewitnesses say Brian then began "horizontally bongoing her boobs back and forth." He says she eventually reached into the center console, grabbed a tissue, wiped him down and then herself and tossed it on the grass.

Someone from the office called the cops and made an indecent exposure complaint. TMZ obtained police audio when the cops came out, and Daniele played the race and fame cards.