PARIS (Reuters) - Support for French presidential hopeful Nicolas Sarkozy showed no sign of taking a hit after a state prosecutor said the former leader should stand trial over funding irregularities in his failed 2012 re-election bid, an opinion poll showed on Thursday.

Surveys in past weeks have consistently shown Sarkozy close on the heels of the frontrunner for the center-right Les Republicains party nomination, former Prime Minister Alain Juppe.

The Harris poll showed Sarkozy, who is fishing for votes in the electoral waters of the far-right Front National, and mainstream conservative Juppe tied on 37 percent of voter support in the Nov.20 party primary first round.

Juppe's support increased to 52 percent in a run-off second round, according to the poll.

While Juppe remains the favorite among the broad constituency of centrist and center-right voters, Sarkozy holds a comfortable lead among the party faithful. The primary vote is open to anyone willing to pay 2 euros and sign a document that they adhere to the values of the center-right, suggesting turnout will be a key factor.

Sarkozy is accused of "knowingly underestimating" elements of his campaign financing. The prosecutor's office recommended earlier this month that he stand trial with 13 others in the so-called Bygmalion Affair, involving spending overruns and allegedly illegal financing.

Sarkozy dismissed the allegations as "shameful" and said he wouldn't be deterred from running in the presidential race.

(Reporting by Richard Lough; editing by John Irish)