Have you posted "Stop pub" on your mailbox and continue to receive ads? Since 1er in january 2021, it is prohibited to deposit unaddressed printed material. That is what the Anti-Waste and Circular Economy Act of Canada says Official Journal of 11 February 2020.
The deposit of unsolicited promotional gifts in mailboxes as well as the distribution of advertising material on windshields of vehicles are also prohibited.
If you find that these provisions have not been complied with, you can contact the brands concerned and remind them that they may be subject to a contravention of up to €1,500 (€3,000 in case of recurrence). You can also get support from a consumer association.
FYI
The scheme ‘ Stop Pub was launched in 2004 by the Ministry of the Environment as part of the first National Waste Prevention Plan. This was achieved by the creation of a sticker which was made available free of charge to individuals who wished to express their refusal to receive unaddressed advertising and thus limit the generation of waste.