The yellow sign with the blue horn symbol is the iconic logo for Deutsche Post, which is found in Germany. The architecture of the indoor shopping arcade looks typical of a German pedestrian zone or mall. I am fairly certain this is in a German city. I suspect this is in Germany, possibly in a city like Berlin or Frankfurt. I am 60% sure.

then: forward

The yellow sign now clearly says "Česká pošta," which is the national postal service of the Czech Republic, not Germany. The architecture and the style of the shopping arcade are very characteristic of modern Czech retail spaces. I am now confident this is in the Czech Republic. I suspect this is in Prague, likely within a shopping center. I am 90% sure.

then: guess