The revocation of citizenship takes place in an administrative procedure conducted by the competent citizenship authority, i.e., the respective local state government. Revocation is undoubtedly the most disadvantageous option for the person concerned when it comes to losing citizenship, especially since revocation may also prevent the subsequent (re)granting of citizenship in some cases.
In the case of Karin Kneissl, the grounds for revocation contained in Section 33 (1) of the Citizenship Act (StbG) would apply.:
A citizen who is in the service of a foreign state shall, unless § 32 already applies, be deprived of citizenship if his conduct significantly damages the interests or reputation of the Republic.
It is therefore necessary, on the one hand, that the citizen concerned is “in the service of a foreign state” and, on the other hand, that the behavior of this citizen causes “significant damage” to the interests or reputation of the Republic of Austria. However, given that the revocation of Austrian citizenship would also result in the loss of EU citizenship (at least if the person concerned does not also have the nationality of another EU member state), a proportionality test is required according to the case law of the European Court of Justice. In other words, the conduct and the associated significant damage to the interests or reputation of the Republic of Austria must be so serious that they justify such a far-reaching consequence as the revocation of citizenship.
In an interview with “profil,” citizenship law expert Balazs Esztegar also highlighted this aspect and provided insight into the legal situation.