Even though this government building is not as interesting as other buildings in Sapporo, it offers a viewing deck on the 19th floor for free!
Wikipedia https://ja.wikipedia.org/wiki/札幌市役所
Official Website http://www.city.sapporo.jp/
Phone +81 011 211-2111
Address Kita 1jo, Nishi 2-chōme, Chūō-ku, Sapporo, Hokkaidō, Japan
Coordinates 43°3'43.312" N 141°21'15.789" E