The character of the Male opera singer is based on that of German tenor Walter Kirchhoff (1879-1951), who traveled to the front in order to perform for the troops. His performance was met by cheers from the French lines, where upon he decided to climb onto no-mans-land to see who was cheering.
The football match depicted was probably inspired by the documented game between the 2nd Battalion The Royal Welsh Fusiliers and the Saxon Infantry who played football on Christmas Day 1914.
In 2008 the British and German Armies sent teams France to play a game of football in honour of their predecessors.
When Lieutenant Audebert (Guillaume Canet) compliments Horstmayer (Daniel Brühl) on his French, Horstmayer replies, "No honor in that; your wife is not German." At the time, Guillaume Canet was married to German actress Diane Kruger, who also starred in the film.
The film is inspired by a book, "Batailles de Flandres et d'Artois 1914-1919" by Yves Buffetaut, and particularly a specific chapter, "L'incroyable de Noël de 1914".
On December 7, 1914 Pope Benedict XV had called for an official truce on Christmas, asking "that the guns may fall silent at least upon the night the angels sing." This appeal was ignored by the leadership. In the years following the Christmas Truce of 1914, artillery was fired on Christmas Day to prevent a repeat of unauthorized peacemaking by the soldiers on the ground.