Former French president Nicolas Sarkozy announced plans to quit his role as head of France's Les Republicains party on Saturday, setting up a potential bid to become head of state for a second time.
Supporters of Les Republicains and other Right and Centre-Right parties will vote in November to decide who will be their candidate in the 2017 presidential election.
The winner will face the far-right National Front's Marine Le Pen and a Socialist candidate, likely to be President Francois Hollande.
Sarkozy would not be able to run in those presidential primaries if he remained head of the party. He would need to resign two weeks before the application deadline on September 9.
"This national council will be my last one as president of Les Republicains," he told a party meeting, calling for a fair contest and no acrimony between the potential nominees.
"This primary will be a time of competition between some strong personalities, between people of significant talent," he said.
"When the right goes into battle it has a front on the left and a front on the extreme right. That is why it is unacceptable that we should attack each other."
For much of this year, Centre-Right rival Alain Juppe has outpaced Sarkozy in opinion polls, but the man who was president between 2007 and 2012 is making a comeback among party supporters, a recent survey showed, a sign the battle could be more open than many thought.