While researching this further, I found this outright wrong statement in an article of the Express (UK), and it is relevant to our forum topic:
"If your previous holidays in Tunisia have been good enough to make you consider buying a holiday home, you need to be tactical as it’s illegal for foreign nationals to purchase property in Tunisia. It’s not impossible, however. “British nationals wishing to buy property in Tunisia have often been advised to do so through a Tunisian ‘friend,’” advises the FCO."
Correct is, that it is only not possible to buy _agriculture_ property (property that can be used for agriculture). Another possibility is, BTW, to rent a property for 99 years. Buying a property in Tunisia requires for foreign nationals a special dispense from the governor, though, but it is usually issued without problems, although it may take some months - this requirement is said to have been lifted for specific building projects (building companies had built too many houses and so they ran into problems of selling them, especially after the VAT has been applied recently to the price...).
Serious advice from me: When you buy something in Tunisia, involve ALWAYS a specialized (!) lawyer. Do NEVER give money to others so _they_ will buy a property that is not in your name (at least have a notarized loan contract about it!). If you do not regard this advice, you WILL LOOSE your money!