Ummm... The EU is, at least at the moment, very specifically 'European'. Malta is in the Med, and is debatable, and snuck in. Turkey has European territory - and its old capital is in Europe. And there is massive resistance to Turkey joining.
Tunisia and Libya are neither one 'European' by any definition I can think of.
Now... If the EEC/EC/EU had expanded onto other continents already, e.g. accepting a hypothetical independent Quebec (which is incredibly unlikely, but France might, MIGHT try pushing for it), then MAYBE Tunisia would stand a chance.
Otherwise you'd have to get some really major changes to the EU to allow it.
The obvious possibility is that the *EU forms on a LondonParis axis rather than a BonnParis axis, and colonies are included from the beginning...