That is the title of the british rockband Magnum's best song.
Magnum is an 80's band with a mix of prog-rock and classic eighties glamrock with heavy synthesizers. They were never a real commercial success so, sadly, not many people know them. The frontman and vocalist Bob Catley is instantly recognized by his amazing vocal talent and distinct sound. Magnum is really a predecessor to all modern "epic" metal bands with their storytelling fantasy-style songs and album covers. As an example Tobias Sammet from Edguy/Avantasia considers both Bob Catley and Les Morts Dansant as big influences on his career choices.
Les Morts Dansant is considered their best song and it's taken from, what is considered, their best album: On A Storyteller's Night form 1985. The song is about a soldier getting executed by a firing squad. If you have any interest in music, you should give this fantastic song a listen!
Les Morts Dansant - Magnum