The title refers to the UN resolution that guaranteed the security of Bosnian civilians in the "safe haven" of Srebrenica.
The film follows a French investigator played by Benoit Magimel, sent by the International Criminal Tribunal for the Former Yugoslavia in The Hague to investigate the genocide in Srebrenica.
The public, who could vote as they left each screening, came out in favour of "Resolution 819" by Italian director Giacomo Battiato after a voting by the tens of thousands of people who attended the 10-day festival, where 150 films were screened.
The Rome Film Festival's Critics Award went to Afghan film Opium War.
Ukrainian Bohdan Stupka claimed the Best Actor prize for his part in Polish comedy With a Warm Heart and Italy's Donatella Finocchiaro took home the Best Actress honour for her role in Galantuomini.
Italy's Donatella Finocchiaro, who starred in the mafia film "Galantuomini" by Edoardo Winspeare, won best actress, while Bohdan Stupka of Ukraine won best actor for his role in the Ukrainian-Polish drama "Serce na Dloni" (A Warm Heart) by Polish director Krzysztof Zanussi.
Also Friday, a lifetime achievement award was bestowed on Italian legend Gina Lollobrigida, whose career has spanned more than six decades.
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