In extradition proceedings, the so-called "Petruhhin mechanism", although applicable during the pretrial phase, always requires citizenship of an EU Member State: this mechanism, actually, does not apply indiscriminately, but only to the benefit of persons for whom the provisions of the Treaty on European Union (TEU) regarding Union citizenship and Article 18 of the Treaty on the Functioning of the European Union (TFEU) give rise to the applicability of the Treaties

The requested person must be informed of the subject-matter of the extradition proceedings. Accordingly, where such information did not cover additional episodes of fraud described in the custodial order subsequently transmitted in support of the extradition request, this gives rise to a ground of nullity. Indeed, in order to safeguard defence rights, once the subject-matter of the extradition proceedings has changed, the judicial authority must order the appearance of the person concerned; failure to do so results in nullity for violation of the right of defence and, consequently, in the invalidity of the acts carried out in the proceedings.