Officially yes, you do.
The procedure isn't easy, since the new bill 67 (december 2015). You'll find a resume here :
https://www.airbnb.fr/help/article/1281/quebec
But this law has has been dicted by hotel lobby. If you want to ask Tourisme Québec for credit, i advise that you ask to you arrondissement first. On the Plateau, only commercial buildings with commercial taxes accounts are allowed. If the arrondissement says no, you kind of snitch yourself to inspectors when you ask for certification at Tourisme Québec.
This law will treat you as if you were opening a big hotel on a commercial street, exactly, aucune nuance. It doesn't make sense, but that is how it was written.
I am renting my garden level with independent entry. If i need it, i won't rent; if family is visiting, i wont rent. If i want to help syrian refugees and host them for free a couple of weeks, i will stop renting. It's my place, i'm the owner. Yet, in bill 67, since my place is officially available more than a week a year (see definitions of location occasionnelle), i should act like i own a hotel.
Good luck with that. I think this law has so many flaws it won't last long without being edited.
http://www.ledevoir.com/economie/actualites-economiques/476700/hebergement-la-loi-anti-airbnb-pratiq...
http://www.ledevoir.com/societe/actualites-en-societe/477891/la-loi-anti-airbnb-est-aisement-contour...
but until then we have to deal with it.