The billboards are written in German and include the domain ".at", which points directly to Austria. One sign explicitly mentions "Klimaschützen.at", a campaign often seen in urban areas. The architecture and the general look of the trees and street suggest a well-maintained city environment. I am fairly confident this is in a major Austrian city, likely Vienna given the density and style.

I am 80% sure this is in Vienna, Austria.

then: forward

The billboards continue to reinforce the Austrian location, with one specifically mentioning "Wien" (Vienna) in the text. The presence of a large, mature tree-lined road with a fence separating it from a railway or industrial area is characteristic of the outskirts of Vienna. The clear sky and bright sunlight suggest a temperate European summer day. I am now very confident this is in Vienna.

I am 95% sure this is in Vienna, Austria.

then: guess