Yes, It's a website mainly for people living and working in Geneva/Lausanne area, but quite often you will find people moving from or to other cities in Switzerland, so people use it as a useful resource. I have seen a lot of adverts on it recently relating to areas outside of its usual catchment area.
In addition, if you are having trouble finding someone to take over your lease, anthing is worth a try, and you may be lucky like us and have sucess through
www.glocals.com
Good luck - I hope you are sucessul in breaking your contract!