Question juridique clé
Whether the administrative appeal against the incidental mutual-assistance order was admissible without proof of immediate, irreparable harm.
Solution extraite
The appellant did not show an immediate and irreparable prejudice caused by the participation of foreign investigators.
Motifs extraits
Such incidental decisions are separately challengeable only if the affected party demonstrates concrete irreparable harm. The safeguards imposed by the MPC, including passive participation and supervision by Swiss authorities, made the alleged risks too speculative.