Sfax is not a place meant for tourists. We didn't fully appreciate this until after we'd left the train station and checked into a hotel. The city seemed clean and safe, but there's just nothing there aimed at tourism. So much so that we found only one restaurant in the town that had French as well as Arabic menus, and that was a pizzeria called Tropicana.
So we decided we'd not be staying in Sfax for long. We checked the bus timetable, then got some rest at the hotel for a few hours. At around midnight we woke up, checked out of the hotel, and went to the small bus station to wait for the bus south. The bus had relentless air conditioning, so we went from being fairly hot to being almost hypothermic. Neither of us had clothing suitable for cold weather.