PARIS - Incoming French president Emmanuel Macron was starting to build his centrist government Tuesday, with his former Socialist boss jockeying for position in a radically changed political landscape.

Macron, 39, was elected France’s youngest-ever president on Sunday, crushing far-right leader Marine Le Pen after a bruising campaign that left France’s traditional parties by the wayside.

He faces a huge task to unite a fractured, anxious country and to win a parliamentary majority in June’s general election, without which he could struggle to implement his ambitious reform agenda.

Macron’s victory at the head of a year-old movement that has presented itself as a home for progressives of all stripes has blown up France’s long-standing left-right political divide.

On Tuesday, former Socialist prime minister Manuel Valls -- a failed candidate for his party’s presidential nomination -- said he wanted to run for parliament on Macron’s ticket.

"This Socialist Party is dead, it is behind us," said Valls, a reform-minded premier from 2014 to 2016 when Macron was economy minister.

"I will be a candidate for the presidential majority," the 54-year-old Valls told RTL radio, while insisting he remained a Socialist and "a man of the left".

Macron’s "Republique en Marche" (Republic on the Move) movement, which has been keeping its distance from the political old guard, reacted warily to the announcement.

A spokesman for Macron’s campaign said Valls "had a good chance" of being accepted into the fold but would have to submit an official application.

Socialist leader Jean-Christophe Cambadelis attempted to prevent a wave of defections to Macron’s camp, warning Valls he could not remain a party member and run for parliament on Macron’s ticket.

"That’s impossible," he said.

A relative newcomer to politics, the europhile Macron swept to victory with 66.1 per cent of the vote on a tide of opposition to Le Pen’s anti-immigration, anti-EU platform.

He has promised to liberalise the economy and rejuvenate France’s jaded governing class by bringing more people who, like him, have never held elected office into government and parliament.

Half of the candidates for the 577 seats up for grabs in the two-round June 11-18 election to National Assembly will be new to politics, Macron has said.

The rest will be from the centrist Modem party or rebels from the Socialists and right-wing Republicans. The candidates will be announced by Thursday.

The losers of the presidential election are aiming to capitalise on a general lack of enthusiasm for the pro-business Macron -- whom many voters backed solely to bar Le Pen -- to bounce back in the parliamentary vote.

The Republicans, Le Pen’s National Front and Socialists all held meetings on Tuesday to discuss strategy.

The Republicans, whose scandal-hit candidate Francois Fillon crashed out in the first round of the presidential election, are hoping to come out tops in parliament and impose their choice of prime minister on Macron.

Republicans grandee Alain Juppe said the party should not adopt a policy of "systematic obstruction" of Macron if it failed to win a majority.

Deficit warning

Macron, who will be inaugurated on Sunday, takes over from his former mentor, the deeply unpopular Socialist President Francois Hollande, who decided against seeking a second term.

One of Macron’s first acts will be to name a prime minister -- a choice that will show whether he leans more to the left or the right.

The former investment banker’s victory over Le Pen has been hailed as the strongest sign that populism may be peaking in Europe after setbacks for nationalists in the Netherlands and Austria.

"Macron carries the hopes of millions of French people and also many in Germany and across Europe," German Chancellor Angela Merkel said.

But Le Pen’s historic score of 33.9 percent, or 10.6 million votes, showed the far right to be a formidable force in a country wracked by concern over immigration, national identity and globalisation.

The fervently pro-European Macron wants to team up with Germany to reform the EU, which has been weakened by Britain’s vote to leave.

Economy Commissioner Pierre Moscovici on Tuesday urged him to tame France’s budget deficit, which is forecast to rise above a eurozone limit of three per cent of GDP in 2018. — AFP