Is there a legally mandated filing fee and/or deposit?

Article 86. (1) No fees or costs may be charged for anyadministrative procedures carried out on the basis of this Act. In the case ofappeals lodged that are dilatory in their nature or that violate the principlesof good faith, the costs may be imposed on the appellant. […]

Federal Act of Political Rights of 17 December 1976 (Status as of 1January 2013)

http://www.admin.ch/opc/en/classified-compilation/19760323/index.html