Brew the fruit tea with 750 ml boiling water and let stand for 10 min., then strain and chill.
Cut melon in half and remove the seeds. With a melon baller scoop out balls, then cut the rest of flesh into cubes.
Rinse berries, trim and put along with melon, raspberry syrup, lemon juice and the fruit tea in a punch bowl and chill for about 2 hours in the fridge.
To serve, distribute the punch in glasses, fill with cold champagne and garnish with lemon balm leaves.