I've lived in Canada. Job-wise, knowing French is always a plus (I lived in Ontario). French is an official language, so even if it's not technically used much by the people of a province (say, Ontario), it's always going to be important and mandatory in all official communication. So it definitely opens doors.
Now, socially, if you live in an English-speaking province, you may not even ever hear French (it's more likely you'll hear Chinese). But job-wise, definitely good to have. Plus, French is a gorgeous language. ;D