As I said, different industry sectors have different regulations, so I wouldn't want to mislead you. Your wife could go to the local customs office with any specific enquiries. It is one of the many frustrations about Tunisia that there is no one stop shop that can give you all the information you need, and often you get conflicting advice. I realise Canada is a long way, but I think a visit is a must before you invest substantial sums. Best of luck and keep us informed.
I was in Tunisia in the last year and plan to visit soon enough thanks again.