Answer regarding 250g less are here in my post: Toronto Mavic Owner: where can I fly?
However, even though you can (as they are toys) you still have to be responsible. That means, if you are not responsible and cause any risk (even if its a toy) then your going to be legally responsible.
Id' also add... think about this - if your flying a drone, people around you do NOT know its 250g or less... get ready to talk to the cops as you will get people calling it in .... so just be ready to expect that .. OH and also understand that when the police are called,the know the bylaws but transport canada laws and drone laws i'm pretty sure most do not (based on conversations i have had with them). so be prepped to prepare yourself with transport canada documentations, the rules, cars etc, have the printed out, ready to hand over.