Go to http://www.hertz.com .

Click "Locations, Cars, and More".

Click "Vehicle Guide".

Put in the location (e.g. "Zurich").

Select the type of vehicle (e.g. "Car/Convertible", "Estate", etc.).

Click each vehicle to determine its size class (even without clicking, you'll see the passenger and luggage capacity and manual or automatic transmission symbols by each vehicle).