I am somehow morbidly fascinated by movies about WW2 POW camps. I have seen quite a lot of them:
Japanese Camps: To End All Wars King Rat Bridge Over The River Kwai Merry Christmas, Mr. Lawrence Empire Of The Sun Prisoners Of The Sun Three Came Home The Great Raid
German Camps: Hart's War The Great Escape The Wooden Horse Von Ryan's Express Stalag 17 Le Caporal Epingle La Vache et le Prisonnier The Colditz Story
PWs / internees - Asia "A Town Like Alice" - original version with Peter Finch and Virginia McKenna. "Changi" - an Australian television mini-series. "Blood Oath" - an Australian television mini-series. "The Dunera Boys" - an Australian television mini-series about interned Europeans sent to Australia
PW - Europe "The Captive Heart" - the first PW film made after WW2, used a real camp as a set
PW - Canada "The McKenzie Break"
PW - Australia "The Cowra Breakout" - an Australian television mini-series, about Japanese as PWs
World War 1 "The Life and Death of Colonel Blimp" - a section of this film "La Grande Illusion" "The Fountain" - internees in Holland
If you are interested in Concentration Camps "Fateless" "The Ninth Day" "The Boy in the Striped Pyjamas" "The Counterfeiters"
Addition to above: "Bent" - set in a concentration camp (more theatrical than realistic)
Ok I am going to say it. Hogans Heroes But seriously there is a movie called Night Porter and it is about how a woman who was a POW ran into one of her Nazi torturers and they have a very strange relationship. Also remember Paths of Glory which about French prisoners in a French POW camp. It is from WW1