By Sarah White and Ingrid Melander
PARIS (Reuters) - Pensioner Jeannine Delaplane, care-worker Cecile Lungeri, and millions like them are giving French presidential candidates and pollsters nightmares.
Less than two weeks before the first round of the election, they still do not know who to vote for, and may not show up at the polling station at all.
Opinion polls show around a third of France's 45.7 million voters might abstain, an unprecedented number in a country with a long tradition of high turnouts. Even among those who intend to vote, about one third have yet to make up their mind on how to cast their ballot.
Reasons range from disgust over scandals involving established politicians to dislike among many voters of all the candidates' personalities or platforms. Added to this is simple confusion: what once looked like a straightforward two-horse race between conservative Francois Fillon and far-right leader Marine Le Pen has produced many surprises.
With voters' intentions so fluid, four candidates are now in with a fighting chance of coming first and second in the April 23 first round, thereby qualifying for the runoff on May 7. By contrast, support for the candidate of the ruling Socialists has collapsed.
All this has cast extra doubt over a campaign whose unpredictability is unnerving financial markets.
Delaplane, 81, is among those agonizing over how to vote. "I just can't choose. I've never seen a campaign like this," she said as she waited to catch a glimpse of Fillon at a rally in the town of Provins, a conservative stronghold east of Paris.
She is hesitating between backing Fillon or far-right National Front leader Marine Le Pen.
However, the mainstream conservative is tainted by scandal - he is under formal investigation on suspicion of financial impropriety, although he denies doing anything illegal - and has slid to third. On the other hand, many voters regard Le Pen as an extremist, along with the far-left's Jean-Luc Melenchon.
A fourth contender, the centrist and new favorite Emmanuel Macron, has never held elected office, was unknown to most of the electorate until nearly three years ago when he became economy minister, and runs a party that is just a year old.
For dental technician-turned-painter Herve Gass, the entire field is unappealing. "I'm in a complete bind," he said at his studio in an historic part of Provins. "I've been put off politics like never before."
Gass, 63, previously voted conservative but said he had gone off Fillon due to the scandal, while he regarded Le Pen as too radical and 39-year-old Macron as too young and untested. As a result, Gass said he might abstain or enter a blank vote.
GRAPHIC: Predictions and polls - http://tmsnrt.rs/2jLwO20
The past six months have seen veteran politicians from the two mainstream parties that have governed France for decades kicked out of the race one after the other, losing party primaries or throwing in the towel because of abysmal ratings.
Instead, Le Pen and Macron are forecast to contest the run-off, with the ex-banker seen winning easily. Still, the first round is no forgone conclusion; Fillon is making a tentative comeback and Melenchon is emerging as the latest sensation thanks in part to his strong TV debating skills.
In percentage terms, support for Macron and Le Pen is in the low twenties and falling, while Melenchon and Fillon are in the high teens and rising; daily polls put as little as 6 percentage points between all four.
Across France, voters of all political stripes have been telling Reuters they're not sure what to make of it all.
"I don't even know if I will vote at all this time," said Lungeri, the 38-year-old carer from Nice who was traditionally a mainstream right voter. "They're all corrupt."
The level of undecided voters has been falling but remains high. While about 80 percent of voters turned out for both rounds of the 2012 presidential elections, predictions for this time remain low, creating a headache for pollsters.
"There is uncertainty for all the candidates," said Francois Miquet-Marty of Viavoice. "If voting intentions remain that close, abstention will play a key role."
Macron, who launched his campaign only in November, has the extra handicap of lacking the support of a well-established party.
Polls consistently show Le Pen as having the most decided supporters, with over 80 percent being sure of their choice, but recent surveys have seen the level of certainty of the Macron vote rise, in one case to over 70 percent.
Miquet-Marty said Le Pen could yet be vulnerable as she relies heavily on support among young and working class voters, two groups where abstention is forecast to be high.
The one election in recent history when turnout was far below average was in 2002. Then, a 28 percent abstention rate helped propel Le Pen's father, National Front founder Jean-Marie Le Pen, into the run-off with only 17 percent of the first round vote. Mainstream voters then rallied behind the center-right candidate Jacques Chirac in the second round, returning turnout to its habitual 80 percent and giving him a decisive victory.
Today the political landscape is more blurred. Analysts say much will depend on who makes the second round. For instance, many left-wing voters would find it hard to back Fillon.
"It's a real challenge for the candidates, they really need to convince voters to go out there and vote," said Frederic Dabi of Ifop pollsters, stressing there was a growing feeling among many that voting "has become pointless".
Voters' loyalty to parties is much more tenuous than it used to be, and some are swinging across the spectrum.
Camille Diener, a physiotherapist from Strasbourg, backed Nicolas Sarkozy, a conservative president from 2007 to 2012, in past elections. This time she is so disappointed by Fillon she has even contemplated a protest vote for Melenchon.
"I don't have a candidate any more," the 28-year-old said, adding that she was ultimately leaning towards Macron.
"This election is just unbelievable," a minister in the Socialist government said on condition of anonymity. "What strikes me, even beyond the high abstention, is how impossible it is to make forecasts: people waver between Fillon and Melenchon, between Le Pen and Macron, based on the most bizarre reasoning."
With the second round to be held in the middle of a long, holiday weekend, many voters might just opt to go to the beach or fishing rather than address their tricky, and in some cases distasteful, election dilemma.
"I'm telling people enough is enough, screw it, stay home!" said Doriane Slamani, a resident of Villeneuve-Saint-Georges near Paris, who for the first time will skip a presidential election. "No candidate deserves my vote."
(Additional reporting by Reuters France reporters; Writing by Ingrid Melander; Editing by Andrew Callus and David Stamp)