In a food processor puree the raspberries.
Pour the liquid through a chinois to remove the seeds.
In a medium saucepan combine the sugar, water, and champagne, and bring the mixture to a boil.
Add the raspberry puree and simmer for 4 to 5 minutes.
Return the mixture to the food processor and blend until frothy.
Pour the mixture into a pan and place it in the freezer.
When half frozen mix the sorbet vigorously with a whisk until frothy.
Return it to the freezer until solid.