From Geneva (airport):
Motorway going towards France
At the Bardonnex border crossing head towards Annemasse and exit immediately (Archamps)
At the roundabout go left (towards Collonges Sous Salève). After Collonges drive about 3km, and turn right.
From Carouge:
At Les Combettes, turn right towards Troinex
At Troinex turn right -> Road opposite the Customs post..