Magistrates have been flown from New Caledonia to Wallis and Futuna after it was established that the territory's prosecutor had no legal standing.
During a court case in Noumea last week, a defence lawyer succeeded in halting proceedings by stating that the Wallis and Futuna prosecutor Atonia Tamole had not been duly appointed by a decree of the French president.
A 1983 law change had transferred some judicial powers from Noumea to Paris, but the prosecutor had still been chosen from Noumea according to the system installed in 1928.
Prosecutions launched in Wallis and Futuna by Atonia Tamole are now considered to be void, raising questions about the status of a major tax fraud case in Wallis.
The news of her sidelining reportedly prompted some accused over traffic infringements in Wallis to challenge the court's authority.