Ontario does not regulate ferrets or other pets, so they are legal in the
province, but some municipalities do have prohibitions or restrictions on
types of pets permitted.  Where we live, the City of York, a part of
Toronto, recently revamped the pet by-laws, allowing ferrets (and a lot of
other pets) where they were previously banned.  I believe they're legal
everywhere else in Toronto except for East York.
 
In any event, you're not going to get a California situation.  I haven't
actively searched, but I don't recall anything in the papers about anyone
ever losing their ferrets to animal control because of them being illegal,
and I was told by a city Animal Control manager that they don't enforce
these laws unless there are complaints or serious biting incidents.
 
Stan & Terrie, with Mookie, Psycho, Cecil, Cocoa & Stash in Toronto
[Posted in FML issue 1785]