If you’ve never visited Quebec or France, you may not even be aware there’s a difference in the language spoken. Interestingly enough, the dialects have evolved much like English has throughout countries of the Commonwealth such as Australia, New Zealand, and the U.S. Remember that French varieties occur even within countries or cities – such as joual, the so-called “working class” dialect in Montreal.
Pronouns sometimes differ: in France, one might say vous to address an older person or new acquaintance, whereas in Quebec one often hears the more informal tu. French-Canadians also tend to rearrange clauses, and may seem to speak faster French (if that’s even possible) because words aren’t as enunciated as they are in France, but some people find the Quebecois more easygoing when it comes to helping learners with the language (rather than giving up and speaking in English immediately, like you may find in Paris).
Word differences vary from amusing (vomir in France, barfer in Canada) to slightly confusing (“you’re welcome” being de rien in France and sometimes bienvenue in Canada; “potato” called la pomme de terre in France and la patate in Canada).
One valuable thing to note – and this goes for almost every language in the world – is that Metropolitan French is often seen as pompous to Canadians, the way a London accent seems posh to people in Leeds, Sydney, or Chicago despite being the same language. Conversely, French Canadians that travel to France are often seen as using obsolete terms, since the French variety used in Canada began centuries ago and much of it didn’t evolve parallel to that of its mother country. The two can understand but might sound strange to each other, the way someone from Texas and someone from Scotland might.
On your trip to Montreal, try to make an effort to learn Canada-specific slang if you learned Metropolitan French in school. And even if you can’t tell the difference – just don’t tell either of them that they sound the same!