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 name from En Marche to La 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.
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.
Although Mr Macron 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
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 support, party secretary general Richard Ferrand said, adding that Mr Macron had now stepped down as party leader given his accession to the presidency.
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.
How is Macron getting on with world leaders?
He has now spoken on the phone to US President Donald Trump. The pair agreed to meet during the gathering of Nato leaders in Brussels on 25 May.
The US statement on the call was fairly routine, noting the "long and robust history of co-operation" between the nations, although a Macron spokesman told CNN the president-elect had pointedly said he would defend the Paris climate change accord, amid growing concern Mr Trump might pull the US out.
An earlier statement from the Macron team said he had also spoken to the leaders of Germany, the UK, Turkey and Canada.