Much like en passant, the replies are forced

A move that a pawn can make to take a piece in chess.

It is an album by the famous Frnch singer Jean-Jacques Goldman. Even though he is not known for anything chess related, he is Frnch. The Fr*nch are looked down upon in chess for some reason, so anything in chess related to this nation has been called "en passant." This includes capturing a pawn that moved two squares, throwing a croissant on the board and starting a revolution turning all pieces into pawns.