I go to Silouhette near Zurich airport in Kloten...the have free weights there although not so many, just dumbells, extra plates and bars. if that's what you are looking then you might try that. Actually they have 4 fitness centers Zurich-wide, I am not just sure if you sign-up now it'll entitle you use your membership in all 4 centers wherever is your prefered location.
I hope this helps.