Clean the fennel, cut in half lengthways and cut into thin wedges. Keep green. Wash tomatoes and cut in half. Bring the wine, vinegar and sugar to the boil, set aside. Coarsely crush the coriander. Heat five tablespoons of olive oil and add the coriander, mustard seeds and chilli flakes. Add tomatoes, sauté briefly, pour in the vinegar mixture and cook over medium heat for about 4 minutes. Season with fleur de sel, pepper and lemon zest. Put warm.

Heat two tablespoons of olive oil with the butter. Season the fish with pepper and salt, fry the skin side vigorously and then let it simmer over a low heat until translucent. Heat the remaining oil and fry the fennel wedges in it for about five minutes. Add the olives for the last minute and taste.

Put the tomato stock in deep plates. Put cod on it. Sprinkle with fennel greens. Serve immediately with fresh baguette.