Not that easy to be precise.
Customs is one legal entity that will prohibit the entering of the merchandise. But you can produce in Canada what is prohibted to import...
Once imported, customs rarely will go after the merchandise ( excluding drugs of course...). In fact, some provincial entity will approve stuff that could be deemed obscene by the customs.
BTW it is worst going into the US with porn than the other way around. In Canada, we distribute movies that are all imported from the US, Europe, Orient .... legally.
Here is a document from customs that should guide you:
