Whether an appeal to the Court of Cassation was available against the fee determination for appointed counsel by the investigating judge
No. For a challenge to the amount of the appointed counsel indemnity, the only available remedy was an appeal to the Tribunal d'accusation; an erroneous indication of a remedy does not create appellate rights.
The decision on costs and the counsel's indemnity fell under Arts. 9 to 11 TFJP. Under that regime, the defense lawyer may challenge a misapplication of the tariff, but when the decision comes from the investigating judge the proper remedy is the Tribunal d'accusation, not the Court of Cassation. A mistaken notice of appeal cannot create a right of appeal.