If you're a non-EU national you can only be employed as a nanny/domestic helper or an au pair via a Swiss government approved agency such as Profilia or Perfect Way. http://www.perfectway.ch/en/for-fami...formation.html http://www.profilia.ch/
"The Law on Foreign Nationals, in force since 1 January 2008, has introduced the following changes:
Au pairs from third countries (e.g. USA,Canada, Thailand, etc.) can only receive permits if they are placed through an agency which is approved and licensed by the Swiss State Secretariat for Economic Affairs (SECO). Currently there are only few such agencies specialising in the placement of au-pairs (e.g. profilia). However, we expect the number to increase throughout the year. Au pairs may now be placed only if they are between 18 to 25 years old."
Obviously, cantons can add their own rules on top of this as evidently Zurich has done.