* Constitutional Court declares list of candidates for 1st round
* Latest poll shows Macron remains best placed to win run-off
* Macron calls for youth military service (Adds poll, Macron army plan, Melenchon march, airport incident)
By John Irish and Gus Trompiz
PARIS, March 18 (Reuters) - Eleven candidates got the go-ahead on Saturday to run in France's presidential election in a vote that independent centrist Emmanuel Macron remains favourite to win.
French voters go the polls on April 23 and May 7 in the two-round election, which is being closely followed outside France as another test of popular discontent with traditional parties and institutions like the European Union.
The campaign has been highly unpredictable, dominated by a fraud investigation into conservative Francois Fillon, which has cost him his place as election front-runner.
French voters will have a choice of 11 candidates after the country's Constitutional Council announced the list of contenders that had met conditions to stand.
In addition to leading candidates Macron, Fillon and far-right leader Marine Le Pen, the list included three candidates who passed the threshold of 500 elected officials just in time: Jacques Cheminade and Philippe Poutou of small far-left parties and centrist lawmaker Jean Lasalle.
The expiry of the deadline would put paid to any further attempts by members of the conservative Republicans party to seek an alternative candidate to Fillon, who is being investigated on suspicion of misusing public funds to pay his wife and children and over a gift of expensive suits.
A BVA poll for Orange released on Saturday showed Macron was best placed to win. He was second in first-round voting intentions, a point behind the National Front's Le Pen who had 26 percent, but would win a run-off against his far-right opponent 62-38, according to the survey.
Fillon has slipped to third in the polls, recording 19.5 percent in the BVA survey, suggesting he would fail to reach the run-off.
Benoit Hamon, the ruling Socialist party's candidate, ranked fourth with 12.5 percent, the poll showed, only slightly ahead of radical left-wing contender Jean-Luc Melenchon.
Several thousand supporters cheered Melenchon on Saturday at a central Paris rally billed as a show of force after he spurned Hamon's overtures to join him.
The left's divisions have favoured the emergence of Macron, a 39-year-old former economy minister of incumbent Socialist President Francois Hollande.
Macron on Saturday said he wanted to restore military service to France for some 600,000 young people each year as part of efforts to face a world entering an era of "turbulence" comparable to the Cold War.
The shooting of a man who attacked a soldier at Paris Orly airport on Saturday refocused attention on security, a major concern after a series of attacks by Islamist militants.
Le Pen blames immigration and shortcomings in the EU for contributing to security risks, and has promised to take France out of the euro zone and hold a referendum on its EU membership.
Her popularity has been a concern for international investors, and a rise in her ratings in another poll on Friday pushed the euro lower.
(Reporting by John Irish and Gus Trompiz; Editing by Adrian Croft)