This may help with the frontalier issue. See links.
However, it seems that with the free movement of people accord, the frontalier zones techncially disappeared in 2007 for eu nationals. But there is still some references to having lived the last 6 months in the zone for G permits. Thus, perhaps this is still in operation for non-EU residents. One doc. notes that in theory the zone is 10 km band around the border, but that it is defined in the Canton accords.
http://etat.geneve.ch/dt/SilverpeasW...chment/Images/ http://etat.geneve.ch/dt/SilverpeasW...chment/Images/