With a well-known crusading judge as its candidate and riding high from a series of prior electoral successes, France's Greens were hoping for a breakthrough in this month's presidential vote.

Instead the party -- and its increasingly under-fire candidate Eva Joly -- has floundered, with Joly languishing in sixth place in polls ahead of the April 22 first round and the environment a non-factor in the campaign.

Experts say Joly, a 68-year-old Franco-Norwegian member of the European Parliament, is partly to blame. Voters have reacted to her coolly and her campaign.

But more important, analysts and party members say, is that with the financial crisis in the fore, environmental issues have dropped off the map for the vast majority of French voters.

"When we ask the French people what will motivate their votes in this election, what subjects interest them, the environment comes last," said Frederic Dabi, an analyst with the IFOP polling firm.

"Eva Joly has had difficulties related to her personality, the lack of a coherent campaign, her gaffes, but this is marginal in relation to the fact that the French are focused on economic and social questions."

There were high hopes for Joly when she was chosen in a primary last year to lead the Green Party, officially called "Europe Ecologie -- Les Verts", in France's two-round presidential vote.

Born Gro Eva Farseth in Oslo, Joly moved to Paris aged 20 to work as an au pair and ended up marrying the son of the family that employed her.

After working as a secretary to put herself through law school, she became a financial lawyer and in 1990 was named an investigative magistrate.

In the 1990s she became a household name while doggedly pursuing a series of high-profile corruption cases against senior officials, banks, executives and the French oil giant Elf.

Her work even inspired a 2006 French thriller, "The Comedy of Power" directed by Claude Chabrol and starring Isabelle Huppert.

The Greens were on a roll when she was nominated, having won a remarkable 16 percent of the vote in the 2009 elections for the European Parliament and 12 percent in French regional elections the following year.

The Fukushima nuclear disaster in Japan was also expected to make the environment an issue in the campaign, boosting the anti-nuclear Greens.

But Joly has not only failed to have much impact -- polls consistently show her with support of around two percent -- party insiders fear her campaign has reversed the Greens' earlier gains.

With her Norwegian-accented French and lecturing manner, analysts say Joly comes across as unapproachable.

And several of her proposals have seemed far out of touch with ordinary voters, such as the idea of scrapping the annual Bastille Day military parade and officialising Jewish and Muslim holidays.

Joly has brushed aside rumours that she will drop out of the race to help the party save face, but admitted things have not been going well.

"When I see in polls that purchasing power is the top concern and the environment the last, I have to say to myself that I have been pretty bad," she recently told journalists.

Top Greens have distanced themselves from Joly, with her opponent in the party's primary, environmental filmmaker Nicolas Hulot, refusing to urge voters to back her and others declining to join her on the campaign trail.

"I cannot be satisfied with Eva Joly's performance, any more than she can be satisfied with her performance," said Noel Mamere, a Green lawmaker who scored the party's best result, 5.25 percent, in the 2002 presidential vote.

"But this isn't linked to Eva's personality," he said. "I do not think that any of us, regardless of their qualities, could have done well in this very simplistic campaign."

Big personalities and simple messages are crucial in presidential campaigns, giving the Greens a major handicap in the vote, he said.

"The environment is the opposite of simplification, it's admitting the world is complex," Mamere said.

Many in the party are now focused on parliamentary elections in June.

Under an electoral pact reached last year with the Socialists, whose candidate Francois Hollande is the presidential frontrunner, the Socialists have agreed not to run against Green candidates in some seats.

Daniel Boy, an expert on the Greens at the elite Sciences-Po school in Paris, said the deal should see them take between 10 and 15 seats, up from only four won in the 2007 parliamentary vote.

But a poor performance in the presidential campaign could also weigh them down, he warned. "Eva Joly has not been able to create a real dynamic in the campaign and this could weigh on the legislative elections," he said.