The French minister in charge of overseas territories, Christian Estrosi, says he will resign if he becomes the mayor of Nice in this weekend's second round of the municipal elections.
Mr Estrosi, who has had the portfolio for nearly nine months, has won most votes in last weekend's first round of voting.
He is already a member of the French assembly for the region.
His announcement comes after the UMP party leadership suggested that those becoming mayors of big cities needed to focus their efforts on their new job.
Mr Estrosi has been criticised in French Polynesia for his reforms that saw early territorial elections under a new electoral system.
The election outcome, however, has upset the UMP which as a result has severed all ties with one of its Tahiti affiliates, the Tahoeraa Huiraatira of Gaston Flosse.