Rinse the fish fillets with cold water, pat dry with kitchen paper and cut the skin slightly diagonally with a sharp knife.
Peel and halve shallots. Rinse the rosemary sprigs and pat dry.
Heat 3 tablespoons of olive oil in a large pan. Season fish fillets with salt and pepper and place skin side down in the pan. Add shallots and rosemary. Fry everything vigorously over high heat for about 5 minutes. Carefully turn the fish and shallots, pour in the white wine and simmer briefly. Remove the pan from the heat and let the fish simmer in the remaining heat of the pan for 2 minutes.
Mediterranean vegetables or just fresh baguette go well with this.