Justin Bieber -- Cleared in Alleged Hit and Run with Paparazzo

Justin Bieber was under investigation for a possible hit and run accident involving a paparazzo overnight -- but police have now cleared him of any wrongdoing ... TMZ has learned.

Justin was leaving the Laugh Factory on Sunset Boulevard around 11:45 PM in his infamous white Ferrari. His pal Lil Twist was there as a passenger, and several paps were on scene shooting the duo.

Once Justin got behind the wheel he motioned for some of the photogs to clear out of the way -- but when he drove off he appeared to pin one of them between the Ferrari and a parked car.

Justin did not stop.

LAPD launched an investigation and interviewed Justin a few hours after the incident ... and he told cops he didn't know he hit the photographer (not a TMZ employee).

Police say the photog was not seriously hurt, but was at fault because he was a pedestrian in the roadway.