Geneva:
0900 83 83 43
There's more information about the service in French at this site.
http://www.sgv.name/site/index.php/U...x_de_compagnie
Side note:
There's also information in there stating that if a veterinary office outside the canton mentions emergency service for the Canton of Geneva, THIS IS NOT THE OFFICIAL VETERINARIAN CARE of the Geneva Society of Veterinarians. I'm guessing this language refers to a veterinarian in Mies (Vaud) who seems to have a bunch of websites holding himself out as an emergency vet in Geneva, which he is not. I've posted elsewhere about that guy based on my own personal, terrible experience. I'm guessing you will be out a small fortune if you call him rather than the actual emergency vet service in Geneva. Stick to the number above.
Also, my own vet is open til 1900 during the week and has Saturday hours if that helps. The info is:
Cabinet vétérinaire de St Jean
Pia Luka and Robert Campbell
28 rue de St Jean
1203 Geneva
022 340 27 27
Dr. Campbell is a native English speaker too (Australian). Good luck!