Joyeux Noël is a 2005 film about the World War I Christmas truce along the Western Front in December 1914 (links are from Wikipedia). Per Wikipedia, "Through the week leading up to Christmas, parties of German and British soldiers began to exchange seasonal greetings and songs between their trenches; on occasion, the tension was reduced to the point that individuals would walk across to talk to their opposite numbers bearing gifts."
This film presents a fictionalized version of one such incident, involving two opera stars (a German tenor and a Danish soprano) who re-unite at the front, and Scottish, French, and German troops stationed in the same area. The film was nominated for Best Foreign Language Film at the Academy Awards and the Golden Globe Awards in 2006.
This year I have read several books and watched a movie for the World War I reading challenge at War Through the Generations. My husband discovered this movie while we were researching the Christmas truce, which I had read about at that site. We watched the movie on Christmas Eve.
Did the movie give a realistic depiction of trench warfare in World War I? There is probably no way to truly convey the horror that these men lived through, but I think this movie did an adequate job. I was certainly horrified. The fear and uncertainty that they all faced daily was shown well. Is the story of the re-united lovers realistic? I doubt it. And the story was too melodramatic.
The review at Reelviews notes that World War I is underrepresented in movies. I agree. After joining the World War I reading challenge (which allowed viewing and reviewing films also), I researched movies about specific wars and found many more on World War II.