In 2009, she signed a petition in support of film director Roman Polanski, calling for his release after Polanski was arrested in Switzerland in relation to his 1977 charge for drugging and raping a 13-year-old girl. In collaboration with Polanski, Reza wrote the screenplay adaptation of "God of Carnage" for the 2011 Polanski film "Carnage". She was nominated at the European Film Awards and won a César Award for her screenwriting and the film won a Little Gold Lion at the 68th Venice International Film Festival.