I am not sure if you have aircon or climate , I have mine on Auto setting set at approx 22 and have no problems .
If you have the air con on and turn it off when the windows clear in my experience the windowsw very quicly mist up again 
What exactly does the auto button do, all it seams to do turn the fans up to full :S so i keep mine of the "face" air vents setting.
The manual says:
Air recirculation system
The a ir recirculation system prevents the
entry of outside air and the air in the
passenger compartment is circulated.
Automatic a ir circulation mode 3
Press button t briefly twice within one
second. t appears on the d isplay .
Air circulation is automatically activated as
soon as the system detects polluting gases
from the outside air. The circuit is
controlled by an air quality sensor.
To deactivate electronic a ir circulation:
press button t again.
At outside temperatures below 5 °C the
duration of the air circulation mode is
limited. This prevents the windows from
misting up. Switch to manual air circulation
as necessary.