In detail:

In Austria, the weight of the drone is sometimes measured in joule. As soon as the drone weighs less than 79 joules (= 250 g at 30 m altitude), it does not need to be registered. The 3 categories A, C and D apply to heavier drones. The categories refer to weight and location (see chart). In all categories you may fly up to 150 m high, provided you have received permission from Austro Control to do so. For categories A and C a form (form for A, form for C) has to be sent to the e-mail address ulfz@austrocontrol.at In addition, an insurance confirmation for a value of 750,000 euros and an ID copy (>16 years) are required. A registration is valid for one year and costs 330 €. The approval process for category D is complex, details can be found on the Austro Control website. The different no-fly zones or control zones are shown on this map. There is also an app for the App Store and Google Play Store.

Exceptions:

For drone flights near airfields you have to contact the responsible person directly.