The download of the app is 100% safe. Immonet GmbH is the developer of Grossmann & Berger which can be found in the Lifestyle category. According to the latest info, the tool is rated 3.2 on Google Play.
This application has been downloaded and installed by over 5K users and its most recent release is dated May 24, 2018. It's free to download the installation package of Grossmann & Berger, also, you can check out users' reviews on Droid Informer. The app works fine on Android 4.0.3 and higher.