Flight tracker pro. For Frankfurt and every airport you get: Live Arrival and Departure boards. Terminal maps. Radar. Food and restaurants. Parking. Ground transportation. Frankfurt International Airport is the largest airport in Germany with more flights to international destinations than any airport in the world. It is the major hub for Lufthansa airlines.
It's safe to download the app. Webport.com is the developer of Frankfurt Airport Pro which is listed among the Travel & Local category. The tool has the average rating 3.3 on Google Play.