The accent is different and some words are different.

Some sounds are different. Queckers "in" are pronounced heavily, almost "ain" (the French from France sounds more like "an"), and so is the diference between é and è that we stress more. When I teach French for people who want to immigrate to Quebec, I start with about 90 different word (for example the last dish of the day is called "diner" in France and "souper" in Quebec), then I teach how we tweak words when we speak fast (which letter to remove, which one to stretch), then the words used widly but not necessarily found in the dictionnary (like instead of "trébucher" (to trip) we use "s'enfarger". Then there is all the expressions which are completely differents, pages and pages of them. It takes hours to cover it all.

A lot of it is the difference in words. If you are really curious this video explained a lot of it to me. http://www.youtube.com/watch?v=dw5Re7k1KBA