Question juridique clé
Whether the appeal was admissible under Art. 84 LTF despite being directed against an incidental decision in a criminal case.
Solution extraite
The appeal was admissible because the file-access ruling raised a mutual-assistance issue involving possible transmission of secret information abroad and presented a particularly important legal question.
Motifs extraits
An immediate remedy was justified where premature disclosure to a foreign state could have the same effect as a final transmission decision. The case also raised a point of principle on how to prevent circumvention of mutual-assistance rules.