Wallis and Futuna will go to the polls next month after the election of the territory's French National Assembly member was annulled last month.
Napole Polutele has retained his seat in June, but the constitutional court in Paris has found that 21 proxy votes were irregular, depriving him of his slim majority.
The French prefect has set the 15th and the 22nd of April as new election dates.
Last year, Mr Polutele was one of the few candidates running for a seat in Paris who secured more than 50 percent of the votes in the first round of voting.
His victory was challenged by Sylvain Brial who came second and who said there were mistakes in allotting proxy votes and also alleged treating.
The French National Assembly election in Wallis and Futuna in 2012 was also annulled because the winner David Verge produced flawed campaign accounts, triggering a fresh election which was won by Mr Polutele.
Mr Verge was subsequently banned from holding public office for one year, but was last elected as the new president of the territory's assembly.