It's cool to find out the location of an old photo. A reverse image search for the church tower gave poor results, but the roof of the building gives the last four letters of the city name. Saarbrücken's first airport was situated in a bend of the River Saar near the church of St Arnual. Wikipedia notes that DLH maintained unprofitable services to the capital of the disputed Saarland for political reasons, and that small planes were therefore used like the He 70G Blitz Buntspecht (spotted woodpecker).

Lufthansa flew the He 70 Blitz on 'lightning services' between Berlin and Frankfurt, Hamburg and Cologne, and between Hamburg and Cologne. It did not last long as the serviceability of the He 70 was poor. Photo from: Lufthansa