This is a scene from Joyeux Noel (Merry Christmas), a Christmas film set during WW1. Scottish, French and German soldiers fraternise on Christmas Eve (based on a true story).
The singing of fictional German tenor Nikolaus Sprink was done by Rolando Villazón.
I'd have liked to put in subtitles, but I'm not even going to pretend to know how. Here's a translation of the non-English dialogue:
German Soldier: They seem to be having quite a party. Don't you want to? This is Anna Sörensen.
Anna: Good Evening.
Soldiers: Good Evening.
German Lieutenant: What is this? Are you crazy, bringing this lady with you?
German Soldier: Lieutenant, I've convinced the Crown Prince that a little music on Christmas Eve won't do any harm.
German Lieutenant: Very well. Start singing, then.
French Soldier: Lieutenant, come quickly! Something weird is happening there!
French Soldier: I don't like the look of this, Lieutenant. Might be a diversion?
German Lieutenant: Sprink! Come down from there!
German Soldier: Good evening, Englishmen!
Scottish Soldier: Good evening, Germans, but we're not English, we're Scottish!
German Lieutenant: Alright, that was nice and all, but we're going back now. This is not the Berlin opera house.
German Soldier: You're right. This is better than Berlin.
French Soldier: Well, look at that. That beats everything. A summit meeting in No-Man's-Land, and we're not invited!
French Lieutenant: Shut it, Ponchel. What kind of mess is this?
French Soldier: What are they doing there?
French Soldier: Maybe the Germans have had enough. Maybe they're surrendering?
French Soldier: That would surprise me.
French Lieutenant: Ponchel, give me a bottle of champagne, and my cup.
