Mix the salmon, parsley, chives, tarragon, paprika and lemon juice.
Spread some of the salmon filling on each piece of sole to within one-quarter inch of the edge. Roll up the sole in jelly-roll fashion, starting with the tail end. Secure with food picks.
Place the sole in a buttered shallow baking dish. Brush the sole with melted butter and bake for twenty-five minutes, or until the fish flakes easily when tested with a fork. Drain sole and remove food picks. Arrange on a serving dish and top with mushroom sauce.