What is this small (unconquered?) white area north east of Italy?

[Theodore Arthur Rabbit]

I'm watching a Netflix production on the Roman Empire. They show this map of all the lands under Roman rule at the time of Tiberius (just prior to Caligula). My question is (and it's driving me crazy) What is the small white area between Italy and France that seems to be independent of Rome? 
  See what I am refering to here:     https://youtu.be/b53uBV1MPSQ

Your help with this burning question is greatly appreciated.