Wash strawberries, remove stems and cut in half. Put in a bowl and sprinkle with the sugar. Wash the lemon in warm water and peel off thin strips of rind with a sharp knife. Finely chop one peeled lemon rind strip and add the lemon juice and chopped rind to the strawberries. Refrigerate. After two hours (the sugar should be dissolved) pour off the resulting strawberry juice and put to one side. Pour wine on the strawberries until covered and refrigerate further for 2 hours. Shortly before serving add the strawberry juice, remaining wine, and sparkling wine and decorate the bowl with remaining lemon strips.