Federal republic with access on various levels
Austria is a federal republic with 9 provinces - the so-called Länder - of which Vienna is one.
On federal level aswell as in all provinces legislation about access to information exists. The provincial legislation also covers the local communities.
However in Austria the approach is a duty of the authorities to provide information rather than a right of the citizen to know, the title of the law being Duty of Informing Law (Auskunftspflichtsgesetz).
The environmental wob is applicable all over Austria, as it is based on an EU-directive, and has been implemented as "Umweltinformationsgesetz" on the various levels.
The division of tasks between the 16 provinces and the federal government is governed by theAustrian constitution (in German and English). Numerous fields however are interacting, and in order to find out, which institution holds the document, you are interested in, you have to go case by case.