By Michel Rose
PARIS (Reuters) - In May last year, then French Economy Minister Emmanuel Macron sat down with Socialist lawmaker Christophe Sirugue in the steel town of Le Creusot and asked him to join his new political movement. He said No. Eight months on, others are saying Yes.
A political outsider who has never run for office and hopes to transcend the classic Left-Right divide, Macron suddenly seems to have a fighting chance of winning the keys to the Elysee Palace and becoming president before he turns 40.
The latest polls show him breathing down the necks of conservative frontrunner Francois Fillon and the far right's Marine Le Pen and he is drawing larger crowds than both at rallies across France.
Macron's rise is beginning to create cracks in the mainstream parties as more and more local officials disregard party orders and defect to the 39-year-old's campaign.
On the right, four former center-right ministers have backed Macron, illustrating Fillon's struggle to rally moderates behind free-market policies harking back to former British Prime Minister Margaret Thatcher.
Macron's magnetic pull is also being felt at the center.
When the management of the small UDI party endorsed Fillon, the party's youth wing sent a furious statement announcing that their 130 elected officials and supporters would back Macron.
A "UDI Youth" sign now adorns the door of a small room at Macron's modest presidential campaign headquarters in the 15th district of the French capital.
Long-time centrist presidential hopeful Francois Bayrou, who may get about 5 percent of the vote, is facing growing calls from his base to throw in the towel and rally behind Macron.
The momentum behind Macron is starting to sow panic too in the ranks of the Socialists, who fear they have little chance of making the runoff in May after five years of uninspiring rule by President Francois Hollande.
Fifty Socialist members of parliament have already joined Macron, according to his team, defying threats of expulsion from their own party.
Even in remote regions of the country, he is attracting more people to rallies than his rivals. More than 2,000 supporters attended his event in the central city of Clermont-Ferrand this month, for example - while former Prime Minister Manuel Valls, who is gunning for the Socialist ticket, only pulled in 300 people there, according to local media.
"There's a real possibility that at some point the dyke breaks and the Socialist party starts hemorrhaging officials towards Emmanuel Macron," Jerome Sainte-Marie, head of pollster PollingVox, told Reuters.
An Odoxa poll this month showed Macron would get 16 percent to 24 percent of votes in the first round in April, putting him within a whisker of Le Pen and Fillon.
In the latest Harris Interactive poll, 41 percent said they "trusted" Macron and he was more popular than Fillon for the first time in a December poll by Odoxa.
Macron followed a path well-trodden by the French elite, attending the prestigious Sciences Po and Ecole national d'administration (ENA) schools and then joining the finance ministry.
He then moved to investment bank Rothschild & Cie in 2008 and made a small fortune brokering a $10 billion deal between Nestle and Pfizer before joining Hollande's presidential staff and becoming economy minister in 2014.
Macron quit in November to focus on his "En Marche!", or "Onwards!", political movement which he established in April.
Written off as a presidential hopeful then, Macron has become France's most popular politician in just a few months, his image a regular feature of Paris boulevard newsstands.
Macron's popularity is an achievement in a country where many hold a disdain for the world of high finance and much of his broad popularity is down to his attempts to bridge the Left-Right divide that dominates French politics.
He made a name for himself criticizing sacred cows of the French "social model" such as the 35-hour working week, iron-clad job protection and civil servants' jobs for life.
But in a country where many often end up voting for the candidate they dislike least, part of Macron's appeal can also be put down to a deep yearning for a fresh face.
He stands out in a race dominated by figures who have been sparring with each other for decades. He is a generation apart from 62-year-old former prime minister Fillon and 10 years younger than Marine Le Pen.
Many Socialist and conservative grandees have long dismissed the Macron phenomenon, deriding him as a shooting star destined to crash and burn in the run-up to the two-stage election.
But with less than 100 days to the election there is no sign yet the media frenzy around him is starting to subside.
One Socialist MP, who declined to be named, said as many as two thirds of the party's lawmakers could swing behind Macron if the Socialists choose one of the most left-wing candidates at their primaries this month.
"Beyond the presidential election, those MPs are getting worried that if Macron remains high in the polls and fields his own candidates in the legislatives, they're dead," he told Reuters.
Analysts warn, however, that as Macron's reform program becomes clearer, especially on how he intends to cut public spending, the harder it will be to appeal across the spectrum.
He has yet to release a full manifesto but, aware of the need to attract left-wing voters, now says he wants to reform the 35-hour working week and the country's wealth tax, rather than scrap these emblematic Socialist policies.
"There are some real question marks hanging over him," said Celine Bracq at the Odoxa polling institute. "His popularity today will not necessarily foretell success in the presidential election."
But others are prudently hedging their bets.
Sirugue, the Socialist MP who turned down Macron in May, told Reuters that the presidential hopeful had since toned down his free-market message and was now more presentable.
"We're not poles apart," said the lawmaker, who replaced Macron at the economy ministry. "If you're asking me who I'd choose between Macron and the Right's candidates, there isn't a shadow of a doubt."
(Additional reporting by Emmanuel Jarry; editing by Richard Balmforth and David Clarke)