"La Porte d'en arrière" is based on the Hank Williams tune, "Honky Tonk Blues." Menard commented, "...I changed the tune some and made up words in French." (Quote in Ancelet, "The Makers of Cajun Music- Musiciens cadiens et créoles")

Re trevek comment, I was speaking of performers unfamiliar with the culture; Both Domino and Hank Williams knew it very well.
But Joe does have a point, I have heard western Canadian farm kids and even a Hutterite girl singing it.