The election of the French National Assembly member for Wallis and Futuna Napole Polutele has been annulled.
Mr Polutele had retained his seat last June but the constitutional court in Paris has found that 21 proxy votes were irregular, depriving him of his slim majority.
He had been 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 had been challenged by Sylvain Brial who came second and who said he found a number of irregularities in the electoral roll, mistakes in allotting proxy votes and also alleged treating.
The previous 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 year but was last elected as the new president of the territory's assembly.