It will give an explosive start to an event which will screen more than 300 films from 70 countries over 35 venues, including outdoor screenings on he famous Copacabana beach.
Elite Squad is the true story of two childhood friends who worked for Rio de Janeiro military police special unit has generated a lot of controversy even before filming started.
The $5m violent action film exposes the brutality and corruption in Brazil's police force.
The script is written by Padilha (best known for the award-winning documentary Bus 174), Braulio Mantovani (City Of God) and Rodrigo Pimentel, former Rio police officer.
'My goal was to convey a dramatic and true account of what it's like to be a cop in Rio,'' says Padilha, who reveals how easy the officers struggling to survive may be drawn to corruption in his country.
Produced by Zazen Producoes, Elite Squad will be released in Brazil right after the festival, on October 12th, by Universal which will also distribute the film in all Latin America countries.
The rights for markets outside Brazil and Latin America have already been sold to The Weinstein Company.
The Premiere Brasil, the main competitive section in Rio, will showcase 37 features and documentaries and 15 short films.
Entries include world premieres of Lucia Murat's Mare - Our Love Story, Murilo Salles' Nome Proprio, Mauro Lima's Meu Nome Nao e Johnny, Paula Gaitan's Diario de Sintra, Carlos Alberto Riccelli's O Signo da Cidade and Toni Venturi's Rita Cadillac, a Lady do Povo.
Sponsored by the City of Rio de Janeiro and Petrobrás, Brazil's state-owned oil company, the festival will also present local audiences with the best of the world's cinema.
The selection includes Cristian Mungiu's 4 Months, 3 Weeks And 2 Days, Carlos Saura's Fados, Wes Anderson's The Darjeeling Limited, Neil Jordan's The Brave One, David Lynch's Inland Empire, Kenneth Branagh's Sleuth and Goodbye Bafana, by Bille August, one of the guests heading to Rio.