Preheat your oven's broiler. Brush eggplant slices with olive oil, and place them on a baking sheet or broiling pan. Place the pan about 6 inches from the heat source. Cook under the broiler for 10 minutes, or until tender and toasted.
Split the French rolls lengthwise, and toast. Stir mayonnaise and garlic together in a cup or small bowl; spread on the toasted bread. Fill rolls with eggplant slices, tomato, feta cheese and basil leaves.