Don't forget the great couscous joints in Marseille, which is about an hour from Arles. Sur le Pouce in the Belsunce neighborhood is a cheap, authentic classic. It might be a bit scruffy on the edges, but they prepare very light and fluffy (double-steamed) grains. Along with the standard options for flavorings / toppings, on Fridays they serve couscous au mérou (grouper). La Kahena, at the edge of Vieux Port, is popular with Algerian pied noir families, and Le Fémina (also in the center) serves barley couscous. (If you go to Le Fémina let me know; when I was last in town, at the end of August, it was closed.) After, amble down to Vieux Port and find the tiny Pâtisserie d’Aix, which has fab Tunisian délices – mouthwater zlabia, makrouth, m’karek, beignets tunisiens, etc. The beignets are fried right among the handful of tables. (By the way, the owners are cousins of the owners of Sur le Pouce; both opened in 1981.) And don't skip the lovely Camargue just south of Arles. (Be sure to try bull meat.) Back in Arles, you'll find plenty of interesting stuff to eat at the massive Saturday street market.