It is believed that the portrait shows Princess Maria Bertha Franciska Felicia zu Rohan.
However, it was not the intention of Oesterreichisch-Ungarische Bank to select this portrait due to the fact it shows a representant of an aristocratic family - and certainly not in 1922, when the First Republic was already established. The plate for this portrait is originally from AUSTRIA P-9, a note dating back to 1904.
In these days the identities of the persons displayed on Austrian banknotes were kept secret. The task of the artist was just to work out a portrait showing an "ideal child's head". He was free to select any model which he deemed suitable.
(Information given by Rudolf Richter, Salzburg - Specialist on Austrian paper money, July 2009)