Thanks for the hint, tried to reproduce it with darktable and got it easier than with Gimp with two instances of the lowpass filter and the equalizer since I don’t have to handle with layers.
Would like to write a tutorial for darktable here but I don’t have a free licensed RAW portrait of a man, preferably an old one.
Currently I am browsing sites like wesaturate.com but I did not find anythin suitable yet.
Maybe someone got a link?