Wipe the raspberries and place in a large bowl. Rinse two of the peaches, remove the stones, and finely dice. Add the diced peaches to the raspberries, then mix in the sugar, orange flavored sugar, and the peach liqueur. Chill the mixture in the refrigerator for 30 minutes.
Pour in the grape juice and chill another 60 minutes.
Pass through a fine strainer into a separate bowl, then add the sparkling wine. Rinse the remaining peach, remove the stone, and thinly slice. Pour the punch into glasses, garnish with two peach slices and the yellow raspberries, and serve.