International students have the same rights reserved as any other employees in Canada. With a legal admission from a company, one could apply for working visa herself or the company will do the job for you. (as most big companies do this, and it is certainly part of the jobs for ppl in Human Resource department)
The discussion ends with illegal-work/payment for part-time jobs. As per part-time jobs, it is also protected by the employment rules/laws. Well, even if the visa student comes up with an agreement with the employer, it is still ILLEGAL that the boss pays less than the regulated amount.
The above is based on what I know and some experience. Hope it helps to other visa students.