Marine Le Pen has announced that she is stepping aside as leader of her National Front (FN) party.
The move comes just a day after the far-right presidential candidate reached the second round of the French election, where she will face centrist Emmanuel Macron.
Marine Le Pen told French TV she needed to be above partisan considerations.
Opinion polls suggest Emmanuel Macron is firm favorite for the second round but Marine Le Pen said: “We can win, we will win.”
The French term Marine Le Pen used signaled that the move to step aside would be temporary.
She told France 2 that France was approaching a “decisive moment”.
Marine Le Pen said her decision had been made out of the “profound conviction” that the president must bring together all of the French people.
“So, this evening, I am no longer the president of the National Front. I am the candidate for the French presidency,” she said.
Marine Le Pen took over the FN leadership from her father, Jean-Marie Le Pen, in January 2011.
She won 7.6 million votes on April 23 – the strongest ever result for a FN candidate, and 2.8 million more than her father won in 2002.
Her party wants to slash immigration, clamp down on trade, and overturn France’s relationship with Europe.
Emmanuel Macron, a former economy minister, is widely expected to win the run-off vote on May 7.
On April 24, he won the backing of President Francois Hollande, to go with that of two defeated candidates.
Francois Hollande said the far right would threaten the break-up of Europe, “profoundly divide France” and “faced with such a risk, I will vote for Emmanuel Macron”.
The president said his former economy minister would “defend the values which will bring French people together”.
Francois Fillon and Socialist Benoît Hamon both urged their supporters to vote for Emmanuel Macron.