Can he close the deal? Inside Macron's daring run for the Elysee

(Repeats profile of Macron published before election)

* En Marche! movement born in aftermath of 2015 attacks

* Macron victory would be setback for European populists

* Economic reform, Franco-German deal at top of agenda

By Noah Barkin , Michel Rose and Emmanuel Jarry

PARIS, April 20 (Reuters) - On Christmas Eve 2015, with France reeling from terror attacks in Paris a month before, Emmanuel Macron sent a letter to the president and prime minister, urging sweeping measures to tackle French inequalities that he believed were fuelling extremism.

The economy minister, who had just celebrated his 38th birthday, didn't expect his bosses to heed his advice, according to aides who described the letter to Reuters.

Macron had been feuding with Prime Minister Manuel Valls for months and grown increasingly frustrated with the slow pace of change under President Francois Hollande.

But the letter was a signal that he was preparing to go his own way, busting the constraints of French establishment politics.

For weeks, Macron and his aides had been discussing the launch of a grassroots movement that would transcend France's long-entrenched left-right political divide. They had conducted a study of foreign movements, including centrist Ciudadanos and far-left Podemos from Spain, far-left Syriza in Greece and the 2008 campaign of Barack Obama.

Now, Macron felt it was time to act. Days after sending his letter he gave his team a green light. Then in late January, over lunch with aides in his ministerial residence at Bercy, overlooking the Seine River, Macron and his aides approved the name of his new movement - En Marche! (Onwards!).

It was the start of an audacious run for the presidency by a man who has captivated the nation by refusing to play by the strict rules that have governed French politics for decades.

Now 39, and running on an independent ticket, he is the leading contender to become France’s next president in what is shaping up as a tightly contested two-round election to be held on April 23 and May 7.

To his fans, Macron is the jolt that France needs – a dynamic fighter for reforms who could pull the country out of its economic malaise and crisis of confidence.

To critics, he is an opportunist selling himself as a political rebel despite serving under Hollande for years and attending the same elite schools that have trained generations of French leaders.

His rivals – far-right leader Marine Le Pen, old-school conservative Francois Fillon and hard-left candidate Jean-Luc Melenchon - fit into well-defined political boxes.

Macron does not. He wants to cut regulations that discourage entrepreneurship, reduce the size of the French state, welcome refugees and promote closer European integration.