Question juridique clé
Whether the appeal is admissible under Art. 84 BGG as a particularly important mutual-assistance case
Solution extraite
No particularly important case was shown; the appeal was therefore inadmissible.
Motifs extraits
The challenged ruling only concerned inadmissibility for late payment of fee advances under Art. 63(4) PA. The dispute raised no point of principle and no departure from settled case law, and alleged arbitrariness or denial of justice in the fee-payment handling did not suffice.