Bercy is a section of Paris after which two sauces are named. Bercy butter is a sauce made with a reduction of white wine with shallots, butter, marrow, lemon juice, parsley, salt and pepper. It's served with broiled or grilled meat or fish. Bercy sauce is a fish stock-based velouté with shallots — a reduction of white wine, fish stock and seasonings. It's served with fish.