There is room for the other 2%
Tunis has had a sizable Christian and Jewish population for most of its history. There are just a few hundred Tunisian Jews left in the city (the majority have gone to France or Israel), and even fewer Tunisian Christians, yet their cultural contributions continue. La Grande Synagogue de Tunis is located on Avenue de la Liberté and is guarded by many police officers and an imposing length of barbed wire. The synagogue is open for Shabbat services, but if you are Jewish, they should be able to open the doors for you to worship anytime you choose.
A massive fig tree shades the largest Greek Orthodox Church in Africa a few blocks down. The Cathedral de St. Vincent de Paul, a Catholic landmark erected by the French, is just across the block on Avenue Habib Bourguiba. The nuns are Italian and Egyptian, and the majority of the patrons are West African and European; Sunday services are offered in Italian, French, and English.