Ali Imran, 30, who was accused of manslaughter, can appeal the decision Dec. 10.
Cristian Nemescu, 27, considered one of the country's most promising directors, and sound engineer Andrei Toncu, 28, died in August 2006 after a car driven by Imran hit their taxi. The taxi driver also died.
Reports said Imran was traveling at least 140 kilometers an hour (88 miles an hour), more than double the speed limit, and that he ran a red light.
Imran was detained by police, then released. He told a court that he was based in Dubai and was in Romania for business reasons.
Nemescu and Toncu were going home after working on "California Dreamin'," Nemescu's first full-length movie.
This year at Cannes, Nemescu's film - left unfinished - won the award called "Un Certain Regard."
Jurors initially decided not to judge the film, which is about U.S. soldiers in a small Romanian village, but changed their minds when they saw it.