From 1989 until this year one could buy a Velo Vignette and stick it on the bicycle frame, the rider was then covered for third party accident damage by the government scheme. The 2011 vignettes provide cover until 31 May 2012.
http://de.wikipedia.org/wiki/Velovignette

Now this year, 2012, the scheme has been scrapped as nearly everyone (90% of cyclists) already have third party insurance (Privat Haftpflichtversicherung) and on some websites there are statements that this risk will be assimilated free of charge after 31 May 2012. But maybe it would be prudent to check you have a "Haftpflichtversicherung" and the cycling risk is covered.

http://www.helvetia.ch/privatkunden/...o_vignette.htm

http://www.mobi.ch/mobiliar/live/ser...flicht_de.html