1 For the fish: Preheat the oven to 220°C (approximately 325°F). Rinse the celery, trim and cut into pieces. Peel the garlic and shallots and chop. Rinse the tomato and dice. Arrange the vegetables in a baking dish. Mix the oil and orange zest together and season with salt and pepper. Rinse the sea bream, pat dry and slice several slits in the thickest part of the fish. Brush the inside and outside of the fish with the oil mixture, fill with herbs and arrange over the vegetables. Bake for about 25 minutes. Remove the fish from the vegetables. Turn off the oven and let the fish rest in the oven with the door ajar.
2 Meanwhile, for the sauce: Rinse the oranges in hot water and pat dry. Finely grate the zest from 1 orange. Peel both oranges with a knife and cut into segments. Reserve the juice. Deglaze the vegetables in the pan with the wine, cook down until almost evaporated then add the orange juice. Bring to a boil then strain. Wipe the pan. Melt the butter, sauté the orange zest, sprinkle with sugar and let caramelize. Add the reserved orange juice, strained pan sauce and orange segments. Season with salt and pepper. Arrange the fish on a serving platter and serve with the sauce.