Soak gelatin leaves in cold water. Mix yogurt with sugar. Squeeze out the gelatin leaves and warm with the lime juice in a small saucepan until dissolved. Remove the pan from the heat, stir ino 1 tablespoon of yogurt, then stir the yogurt-gelatin mixture into remaining yogurt.
Beat heavy cream until stiff and fold into the yogurt mixture. Divide half of the yogurt mousse among glasses and refrigerate briefly. Meanwhile, sort the berries, rinse and pat dry gently. Halve depending on the size or leave whole.
Spread half of the berries on the yogurt mousse in the glasses. Pour remaining yogurt mousse on top, and finish with the remaining berries. Refrigerate for at least 30 minutes. To serve, garnish with mint leaves.