The Federal Act on Acquisition of Real Estate by Persons Abroad was adopted on December 16, 1983, by the Federal Assembly and came into force on January 1, 1985. This Swiss federal law, also known as the Lex Koller, limits the acquisition of real estate by persons abroad. It succeeded the Lex Friedrich and was extensively amended in 1997 to take the name of Federal Councillor Arnold Koller, then head of the Federal Department of Justice and Police.