No. There are no Canadian laws banning interview Qs about previous salary, wages, bonus, etc. a la some state laws in the US. But Ontario ALMOST adopted one.
In 2017 or 2018, Ontario adopted a so called pay transparency law which, among other things, banned employers from asking job applicants how much they made with previous employers and list salary ranges in publicly posted job ads. But in June, the Progressive Conservative party won the provincial elections and began peeling back the employment law reforms of its Liberal Party predecessors, including the pay transparency bill which had been slated to take effect Jan. 1, 2019. Technically, the new bill (Bill 57) doesn’t revoke but freezes the pay equity law to a date to be determined by the government. Of course, the suspicion is that the current government won’t ever set a date and that it will take another regime change to make pay transparency a reality in Ontario.
Had the pay transparency law gone through, Ontario would have been the first Canadian jurisdiction to ban interview Qs about previous salary. In other words, such Qs are legal in all parts of the country. Hope that helps. Glenn