A William Holden (Oscared) jag from Network. IMDB tells me this was a sympathy Oscar for him missing out for Sunset Boulevard, which Billy Wilder also co-wrote and directed. The opening voice over claims there haven't been (m)any POW movies before this one, but didn't the genre just explode. The Sergeant Schulz here (Sig Ruman) is a bit soft hearted and apparently soft headed, the other German soldiers often incompetent or too trusting, making it look like the template for Hogans Heroes. Otto Preminger plays the Commandant. It's mostly comedy/farce with a serious (tendentious) undercurrent: that it might be reprehensible but is certainly no sin to be a privateer/capitalist in wartime conditions; that a "stoolie" surely couldn't be a fellow American. I struggled to get into it.
Bosley Crowther dug it at the time. An adaptation of a stage play. IMDB suggests that Holden was as unimpressed as I was.