Heat grill to medium. In a small bowl, combine lemon zest, Italian seasoning, red-pepper flakes, anise seed, 3/4 teaspoon salt, and teaspoon pepper. Set spice mixture aside.
Place four 14-inch squares of heavy-duty aluminum foil on a work surface. Dividing evenly, place onion on one half of each square (leaving a 2-inch border), followed by the zucchini; season with salt and pepper. Top with fish; sprinkle with spice mixture. Top with tomato; drizzle with oil. Fold foil over ingredients; crimp edges to seal.
Place packets on grill. Cover and grill until fish is just cooked through, 10 to 12 minutes. Remove packets from grill; open carefully (hot steam will escape), and transfer fish Provencal to serving plates.
This recipe is from Emeril Lagasse's column, Kick It Up.