Below, a link to J. B. Bullet singing 'Je suis Charlie', a protest song that has gone viral. Two chorus lines read:
'Un coup d'Kalach pour un coup de crayon
Tu salis ta religion'
This refers to the work of a pencil being replied to by a Kalashnikov, and states that the perpetrator is soiling his religion. The music recalls a much earlier song: Renaud's 'Hexagone'. This was a very different kind of protest song though: on Sunday the police were applauded as their vans went carefully through the crowd, whereas Renaud's protest was very different indeed. Times change. (Renaud, incidentally, once declared that Charlie Hebdo is the first paper that made him laugh.)
Links to both songs: