In a bowl, put the blueberries, raspberries, sliced strawberries, and peeled peach cut into thin wedges. Mix well and add the sugar, blackcurrant liqueur, and thinly julienned mint.
Mix everything carefully so as not to break the fruit and marinade in the refrigerator for at least 1 hour before using.
To serve, put a generous spoonful of mixed berries in each glass and add the cold sparkling wine.
*Instead of wine glasses, you can prepare everything in a jar and stir a little before serving.
