Just in case for reference from Sixt Germany:
Territorial restrictions
The vehicle selection can restrict travel to certain countries. For a description of these restrictions on admission, the countries are divided into three zones.
Zone 1: Andorra, Austria, Belgium, Denmark, Finland, France, Germany, Gibraltar, Great Britain, Ireland, Italy, Liechtenstein, Luxembourg, Monaco, Netherlands, Norway, Portugal, San Marino, Sweden, Switzerland, Spain and Vatican
Zone 2: Croatia, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia and Slovenia
Zone 3: All countries which are not in zone 1 or 2.
Jaguar, Maserati, Land Rover and Porsche cars as well as all luxury cars may enter only in Zone 1 countries. Audi, BMW, Mercedes-Benz and Volkswagen cars up to group L*** are allowed to enter only in Zone 1 countries as well as Poland and the Czech Republic, while X*** cars are only allowed to enter in Zone 1 countries. Vehicles of all other brands may enter only in the zones 1 and 2.