By Emmanuel Jarry
PARIS (Reuters) - Francois Bayrou, a failed centrist candidate in three past French presidential elections, was set to announce on Wednesday whether he will run or not in this year's tight race for the Elysee, a choice that could have an impact on the outcome.
Opinion pollsters give Bayrou single figure percentages in the April 23 first round, and therefore only a tiny chance of winning.
However, if he decides to stand, he could leach away votes from Emmanuel Macron, another centrist who is among the leaders, but whose campaign has lost momentum according to the polls.
He may also decide to back Macron, or simply to stand down and take no part.
A supporter of the unsuccessful Alain Juppe in November's conservative primaries, Bayrou, 65, an education minister in the 1990s, has already ruled out backing the winner of that contest, Francois Fillon.
Bayrou has said he will give his decision at around 1630 local time (1530 GMT) at the headquarters of his political movement MoDem in Paris.
Polls show Fillon, a former conservative prime minister, and Macron, an ex-investment banker and economy minister, battling neck-and-neck for second place in the April 23 first round of voting, in which far right National Front leader Marine Le Pen is set to come first.
Either man would beat her in the second round, the polls show - although she has been narrowing the deficit in recent surveys of voting intentions.
Both Le Pen and Fillon are embroiled in financial scandals.
Le Pen has denied allegations by OLAF, the European Union anti-fraud agency, that she gave parliamentary assistants fake jobs paid for out of EU funds.
French judges opened a fraud investigation on Dec. 15 after prosecutors handed the dossier over to them following a preliminary investigation of more than a year.
Fillon faces an investigation into allegations that his wife did no real work for the hundreds of thousands of euros in taxpayers money she was paid in past years. He has said the work was genuine.
Earlier on Wednesday, Francois de Rugy, who stood unsuccessfully as an ecology candidate in the primaries of the left that elected Socialist Benoit Hamon as candidate, said he would back Macron for the presidency.
De Rugy won 3.82 percent of the vote in those January primaries, and has been critical of Hamon's policies.
"I draw this conclusion today that I want to take part in the renewal of politics that Emmanuel Macron has launched," he said on France Info radio.
Environmentalist politics are split in France.
Greens party candidate Yannick Jadot, who is standing for the presidency himself and whom polls show picking up between 1 and 2 percent of the vote, is in talks with Hamon about an electoral pact under which Jadot would withdraw in Hamon's favor.