Reggio, I don't think that's true in my city. I called City Hall and as long as my business only takes up 25% of my rental space I'm legal. There is no other zoning bylaw regarding business/residential. My superintendant was worried that the landlord might get mad but I have been in business 4 years now without hearing anything from them so I don't think they mind because I'm careful about the hydro, water, etc.

However, it's a good point and worth checking with City Hall Bylaws in your city soph.