Several mountains to climb for young and untested leader Emmanuel Macron

French President-elect Emmanuel Macron celebrates on stage at his victory rally near the Louvre museum. Photo / AP

Emmanuel Macron's convincing election to the French presidency will have been greeted with sighs of relief on both sides of the Channel.

But in London, Brussels and Berlin, the installation of such a young and untested politician in the Elyse Palace should give as much cause for trepidation as for celebration.

With the clock already ticking on the two-year Article 50 talks, Macron offers much-needed stability in Europe but beyond this would appear to offer scant comfort to British Prime Minister Theresa May when it comes to the Brexit negotiations.

As an ardent pro-European who espouses the supranational politics of the EU so recently rejected by Britain, Macron can be expected to continue with France's already tough stance on Brexit.

But Macron's victory is also bitter-sweet for Brussels and Berlin.

Their preferred man won, but not before nearly 50 per cent of French voters had demonstrated in the first round their lack of faith in the European Union's ability to deliver security and prosperity while preserving France's national identity.

Macron now has several mountains to climb.

Next month his En Marche! movement will try to win him a parliamentary majority without having either state funding, or a battle-hardened campaigning machine to propel it through France's two-round electoral system.

The extent of his success or failure will determine his chances of meeting the next challenge - reuniting France and delivering real, material improvements to those angry, forgotten suburbs where factories are closing, companies do not invest, and where the educated leave, never to return.

Delivering on that promise - to cut household taxes, boost training and improve job opportunities - while putting France's fiscal house in order, cutting the proportion of spending by a bloated state from 57 per cent of GDP to 52 per cent, will be key to success in his third challenge.

That is, to re-boot Europe.

To reinvigorate the ailing Franco-German axis by increasing defence co-operation and convincing Germany to back deeper Eurozone integration, mutualising debt and creating common insurance schemes for the Eurozone's savers and the unemployed.

Only if Macron can put France's divided house in order will he have any prospect of convincing Germany to give up on the idea that it is just paying for the profligacy of others, and create a Eurozone capable of weathering the next financial crisis.

Given the levels of anger and dislocation visible in the election campaign, the conditions are not propitious for Macron to succeed.

He needs to look no further than Italy, where Matteo Renzi - another bright-eyed, silver tongued centrist - burst onto the scene promising big things at the tender age of 39.

However, he was brought down to earth by a combination of his own arrogance and the continued fracturing of the old political establishment.

Macron will be helped in both Brussels and Berlin by the implicit threat that failure on these three goals could open the door to the National Front's defiant Marine Le Pen in 2022.

But he will be equally hindered by the deep divisions that leave the 27 EU member states consistently incapable of confronting their most profound challenges.

The burden of getting the EU's house in order now falls heavily on Macron's young and inexperienced shoulders.