The Café de Paris, at the bottom of Avenue Bourguiba near the medina gate, is the best terrace on the boulevard for watching the evening promenade. The coffee is good, the service direct, and the people-watching excellent. It is a proper Tunisian café rather than a tourist operation — you will share the terrace with students, civil servants, and old men reading newspapers.
Order a double espresso or a Tunisian tea (heavily sweetened, served in a small glass). The café also does a creditable citronnade (fresh lemon) if the heat has got to you. The covered arcade shelter makes it usable on the occasional rainy winter day. Open daily from early morning until late evening; busiest at midday and from 6–8pm.