I do not mean the Eco/Fast/Normal mode. On the climate controls.
When you press the gear icon on the edge of the Touch 2 system and go to Vehicle menu.
(Engine must be turned on, wait until it goes from greyed out to selectable.)
Select vehicle customization. (translated from Dutch) select Climate Customization. Then you can check Efficient Ventilation Mode.
Strange. Can't find anything like that in the manual. Checked all available options under vehicle customization, but nothing related to climate control. Seems I'll have to wait for my car to check it live