The plot follows an upper-middle-class French couple, Georges (Auteuil) and Anne (Binoche), who are terrorised by anonymous tapes that appear on their front porch and seem to show the family is under surveillance. Clues in the videos point to Georges's childhood memories, and his resistance to his parents' adopting an Algerian orphan named Majid, who was sent away.
The film has been interpreted as an allegory about collective guilt and collective memory, and as a statement on France's Algerian War and colonialism in general. It won three awards at Cannes, including Best Director; five European Film Awards, including Best Film; and other honours. It was controversially disqualified for the Academy Award for Best Foreign Language Film. Caché has been regarded in the years since its release as one of the greatest films of the 2000s, included in BBC's 100 Greatest Films of the 21st Century.
Source: https://en.wikipedia.org/wiki/Cach%C3%A9_(film)