During the fight with the Sun-Eater, the Sun is shown burning yellow. It's actually white; it only appears yellow as viewed from Earth because of how the visible color spectrum is filtered through the atmosphere.
When Lex is giving his speech about Obsidian Platinum in Sao Paolo, Brazil, the background behind him is actually Rio De Janeiro, Brazil.
When the Luthors are playing chess, the chessboard is set up sideways. A chessboard is supposed to be set up so that each player's lower right-hand square is white, but in the Luthors' game, it is black.