How far can it be argued that your chosen films provide a 'realistic' representation of the people and places they focus on?

City Of God is set in Brazil throughout the 1960's and 1970's. On the bonus DVD, it is revealed that the only professional actor with years of filming experience was Matheus Nachtergaele, who played the supporting role of Carrot. Most of the, cast were from real-life favelas, and in some cases, even the real-life City of God favela itself. These actors from real-life favelas give the film authenticity as they personally know how these gangs of drug dealers act and how they stay on top of their favelas. the film 'City Of God' even though it was based on a book was loosely based on a really story from the City of God with characters very similar to them in the film