A unique version of French
Quebec French is the main variety of French spoken in Canada. Quebec French is made of a majority of lexical items that also exist in other dialects of French. However, many words and expressions are unique to Quebec, which makes it comparable to the specificity of American and British varieties of English.
Here is a funny video about what can be the consequences of those differences:
Here is an activity based on the above video that you can do with your French class (level: C1, C2):
Why is the French so different in Quebec?
The differences between Quebec French and metropolitan French are historical.
The people of Quebec, formerly named New France (French colony of the 17-18th centuries) used to speak a variety of French similar to one spoken in Paris. However, situated in different realities, different contexts, they both evolved differently.
Quebec French evolved through interactions with English and political measures, which aims to preserve the language surrounded by English-speaking regions.