WIPA (Wiener Internationale Postwertzeichen Ausstellung, or, in English, Vienna International Philatelic Exhibition) is a major stamp show held in Vienna from time to time, most recently in 2008.
Poster stamps (i.e. advertising labels that look like stamps but have no postal use) have often been issued by WIPA to commemorate the event, and this single label is one that was originally part of a set issued for the 1965 show. It depicts the Vienna skyline in 1672.
U/M / Unmounted Mint / MNH / Mint Never Hinged.