Coat the fillets with a light dusting of flour. Heat olive oil, add chopped rosemary and the fillets, skin side down, and fry for about 3-4 minutes. Meanwhile cut a lemon in half. Use a small knife to cut around each individual lemon section. Remove the sections from the skin, saving the juice. Carefully flip over the fillets, reduce the temperature, add the lemon segments, cook for a further 1-2 minutes. Add the lemon juice, remove the pan from heat, stir in some butter, let sit awhile. Serve with baguette.