
Polygonia c-album aka “Comma”
This is probably one of the easiest to identify species of butterfly in Europe, especially when the underside is visible like in this photo. Not only can you see the name-giving "Comma" (in the German common name, it's simply a "C"), but also the silhouette is very characteristic - it always reminds me of an artistic paper-cutting.
The colour of the underside can vary from light / golden brown or yellowish to grey and even very dark brown.

The Comma is a species of butterfly belonging to the family Nymphalidae. Its irregular wing edges are characteristic of the "Polygonia" genus, which is why they are commonly called anglewings. It is found in northern Africa and across Europe from Portugal through Asia as far as Japan. Its dorsal wings are colourful but its underside has a pattern that camouflages it when its wings are held together.