Depends on the job, if you're trying to get a client service/restaurant/selling or that kind of jobs where you have to interact with clients, then you need to speak a bit of french.
+ you might add the fact that we are in election atm, so the french debate is still going on
If you want to get a job where you talk to your boss and other employees only, then there shouldn't be any problem.
Where and why are you coming to montreal ?