Emmanuel Macron took his first steps as France’s president-elect on Monday but faces a tough task establishing a team that can govern effectively.
His party has announced it is changing its name from En Marche to Republique En Marche (Republic on the Move).
It must pick candidates quickly ahead of parliamentary elections on 11 and 18 June. It wants to be the biggest party but at the moment has no seats at all.
Mr Macron beat the far right’s Marine Le Pen by 66.1% to 33.9% on Sunday.
But a low turnout and a record number of spoiled or blank votes showed disillusionment among many, particularly on the far left, at the choice they were given.
Ms Le Pen has also signalled there will be a change to her National Front party. There are suggestions from its officials, too, that it will change its name. But she has vowed to lead the “new force” into the parliamentary elections.
First day as president-elect, by the BBC’s James Reynolds, Paris
Emmanuel Macron inherits one of the most powerful positions in Europe, and all the symbolism that comes with it.
This morning at the Arc de Triomphe, he showed no sign of being awed by his new job.
He walked alongside the outgoing President, François Hollande, as the two laid a wreath at the Tomb of the Unknown Soldier.
They then shook hands with veterans. Mr Macron appeared to take longer to make his way through one receiving line, stopping to talk to elderly men, leaving Mr Hollande to wait for him at the end.
Emmanuel Macron now becomes France’s youngest leader since Napoleon Bonaparte, whose battles are commemorated at the Arc de Triomphe. The new president will hope that his own fights are less bloody.
How difficult could it be for Mr Macron to govern?
He faces two main problems – a complete lack of representation in parliament and a deeply divided country.
Apart from being, at 39, the country’s youngest president, he is also the first from outside the two main parties since the founding of the modern republic in 1958.
Although he won support, sometimes grudgingly, from the established Socialists and Republicans, much of it stemmed from the need to beat Ms Le Pen. The conservative Republicans in particular will be looking for a strong showing in the parliamentary polls.
How to do the opinion polls stack up?
Polls released shortly after Mr Macron’s victory suggested he and his allies in the centrist Modem party would come out top in the first round on 11 June, with 24%-26% of the vote.
Both the Republicans and National Front would have about 22%, the far-left France Unbowed 13%-15% and the Socialists, still smarting from François Hollande’s unpopularity, 9%.
But the first-past-the-post system means it is difficult to gauge seat numbers. The National Front only has two seats and despite its candidate’s performance in the presidential election, one poll suggested it might only get 15-25 in the 577 seat parliament.
Such uncertainty means Mr Macron might well be faced with a serious amount of horse trading to find allies to buy into his manifesto.
Another opinion poll in Le Figaro on Monday suggested many French people think this no bad thing.
The Kantar Sofres-OnePoint study suggested only 34% of those interviewed hoped the new head of state would have a majority in parliament.
The BBC’s Lucy Williamson says Mr Macron’s experience as economy minister has taught him that building cross-party consensus for each individual issue can be draining and dispiriting. Much will depend on whether his party can form a stable coalition.
Why the party name change?
It is part of the move to widen Mr Macron’s support, party secretary general Richard Ferrand said.
Mr Macron intends to field candidates in all seats and has said half of them will be newcomers to politics – to try to introduce new blood. Half will be from Modem or defectors from other parties.
The idea is that the candidates will not have to give up their party affiliations but will need to run under the Republique En Marche banner.
Macron: The days ahead
Tuesday 9 May: Mr Macron will mark the EU’s Europe Day, the annual celebration of peace and unity in Europe. Much of his victory speeches on Sunday focused on the need for a strong Europe
10 May: Marks France’s Slavery Remembrance Day, then in the afternoon attends the funeral of Corinne Erhel, the legislator who collapsed and died while speaking at a Macron rally last Friday. Official election results are published
14 May: President François Hollande formally hands over power to Mr Macron, who will start to announce his ministers, including a PM. He says he has made his choice for the post. It could be a woman, with one name touted that of former economy minister, Christine Lagarde
15-19 May: Mr Macron must finalise candidates for his party in the parliamentary election
11 and 18 June: Parliamentary election held over two rounds. All 577 seats are being contested in a first-past-the-post system
And the National Front?
Officials have suggested there will be a new name – also to broaden support.
Despite Marine Le Pen’s efforts to refocus the party, it has continued to suffer from its past extremist associations under her father Jean-Marie Le Pen.
Nicolas Bay, party secretary-general, told the Associated Press: “The National Front is a tool that will evolve to be more efficient, bring even more people together after the number of voters we reached last night.”
Ms Le Pen hailed a “historic result” but admitted the need for “profound transformation” before the parliamentary elections. She said she would stay to lead an opposition of “patriots” against “globalists”.