By Geert De Clercq

PARIS (Reuters) - When Nicolas Sarkozy won the French presidency in 2007, the roaring Noughties were still in full swing and his message of "work more to earn more" was in sync with the times.

Five years later, sobriety, solidarity and a desire for fairness define the zeitgeist and Sarkozy's Socialist challenger Francois Hollande seems more in tune with the spirit of the age.

Winning an election requires a potent mix of charisma and a project that captures the public mood. Sarkozy's 2007 Socialist opponent Segolene Royal had plenty of personality but, with the economy growing and the stock market booming, her message of social justice did not fly.

This time, the mood is very different. With both contenders vowing to balance state books, voters know the coming years will be austere and they are looking for a leader who makes everyone share the sacrifice while safeguarding the welfare state.

Style matters too. The French are fed up with a "bling-bling" president seen as a friend of the rich. Hollande's modest manner is reassuring and his vow to make justice his guiding principle speak to the anxieties of this decade, the Teenies.

If he wins the May 6 runoff - as all polls predict - his style and message will be studied well beyond France's borders.

"In 2007 Sarkozy embodied dynamism and optimism, but now the French are fearful. They want more regulation and a president who protects them," said Alain Duhamel, the dean of French political commentators.

For Christian Salmon, a writer on French politics, the neo- liberal revolution that began in the early 1980s with Ronald Reagan and Margaret Thatcher hit the buffers with the global financial crisis of 2008, but no new ideology has yet emerged.

"While we wait for the emergence of a new political paradigm, the new leaders in Europe today all have more of an ethos than an ideology: the ethos of the bespectacled accountant who will restore order in the country," he said.

Salmon said the crisis has made the traditional divide between conservatives and social democrats less relevant than a new split between exuberant but distrusted showmen like Silvio Berlusconi and Sarkozy and duller but steadier personalities like Italy's Mario Monti, Spain's Mariano Rajoy and Hollande.

"It is a time for modesty and ethics that started in 2008 with Barack Obama," Salmon said.

Outside the political sphere, some were early to sense the changed spirit of the age. In January 2009, less than a year into the crisis, German-born Chanel designer Karl Lagerfeld heralded a "New Modesty", saying that bling was over and that the crisis would bring a big moral spring cleaning.

DOUBLE CHIN

Hollande's plan to raise taxes on banks, big companies and the rich appeals to a deep desire for fairness after a decade in which inequality rose to 30-year highs.

So does his promise to be a "normal" president, answerable to the courts like any other citizen. Hollande has said his government's first decision would be to cut presidential and ministerial pay by 30 percent and he pledges to travel in France by train instead of presidential jet when possible.

Even his weight loss fits the modesty message, said Salmon.

"You can't preach austerity with a double chin," he said.

The spirit of an era is hard to fathom, but polling agency CSA has tried to measure the difference between society as perceived and society as desired.

CSA presented 1,000 voters with 19 keywords picked from the 2007 and 2012 campaign slogans and asked which best represented the state of French society and which best described their personal state of mind.

The two most-used words to describe society were "profit" (53 percent) and "capitalist" (43 percent), while the two that respondents most used to describe themselves were "change" (28 percent) and "solidarity" (25 percent).

Only 4 percent picked "justice" as a good description of the state of France, while 22 percent said it was a personal aspiration.

"There is a very strong egalitarian critique of the economy in France at the moment," said Jerome Sainte-Marie, head of political studies at CSA.

He said French people know there will have to be belt-tightening to repair public finances and they want the pain to be shared fairly.

"They do not trust Sarkozy for that because he is seen as the president of the rich," he said.

In 2007, the last year of the debt-fueled prosperity of the Noughties, Sarkozy appealed to voters with the idea that everybody would be able to get rich. Disappointed voters now want a fair captain to steer them through the storms ahead.

"By constantly hammering on the theme of social justice, Hollande is clearly in sync with the times," Sainte-Marie said.

HATRED OF THE RICH

In his keynote January 22 speech, the Socialist declared that the world of finance was his main opponent and put the issue of fairness at the centre of his campaign.

"The French people must know that as president I will ask only one question: before every extra effort, before every reform, every decision, every law, every decree, I will ask myself one single question: 'Is it fair?'" he said.

The dominant theme of the 2012 election jumps off the April 19 "Hatred of the Rich" cover of weekly Le Point, which superimposed the faces of French opposition politicians onto Jean-Victor Schnetz's celebrated "Fighting at the Hotel de Ville", a painting of a street battle during the July 1830 revolution that toppled the restored Bourbon monarchy.

Centre stage was Communist-backed hard-left leader Jean-Luc Melenchon, who drew massive crowds to rallies and at one stage rose to third place behind Hollande and Sarkozy before falling back to score 11.1 percent in the first round.

"People want more justice, but not a complete social break, or they would have voted communist," CSA's Sainte-Marie said.

A NEGATIVE OBAMA

Despite his egalitarian and regulatory program, the consensus-seeking Hollande is an unlikely agent of change.

Unlike Sarkozy, whose Hungarian origin and lack of elite education made him an outsider in the 2007 race, Hollande is a dyed-in-the-wool Socialist apparatchik, who graduated from the exclusive ENA school that trains France's elites and ran the party for 11 years. Even within his own ranks, some describe him as bland and soft as pudding.

Christophe Prochasson, a historian of the French left, sees Hollande as a man devoid of ideology. "A doctrine is important in politics. It gives meaning to your action," he said.

Yet Hollande's middle-of-the-road image might be his strength.

"In a way, Hollande is a negative Obama. Obama was the surface upon which everybody could project their dreams, because of his personal charisma. Hollande creates the same effect: he is so nondescript that you can also project all your dreams on him," said philosopher Michel Feher.

Hollande's impact on France and Europe - and maybe even on the zeitgeist - will depend on how he translates his call for justice into policy, if he wins.

Economist Thomas Piketty, who inspired Hollande's plan to tax income over 1 million euros at 75 percent, believes Hollande could become a French Franklin Roosevelt, like the U.S. president who in the 1930s reduced inequality with higher taxes and created jobs with public investment.

When he launched his candidacy a year ago, Hollande looked lonely with his call for higher taxes and more regulation.

But by the time the campaign got into full swing this spring, all 10 first-round candidates, including Sarkozy and far-rightist Marine Le Pen, were proposing tax increases and more regulation.

And while Hollande was a voice in the wilderness calling for a response to the euro zone crisis more focused on promoting growth than on austerity, he is now rapidly winning converts, even in the government of conservative German Chancellor Angela Merkel.

Yet most major European countries are led by conservative governments, recent elections in Britain, Portugal and Spain have seen a swing to the right, and financial markets are bound to punish any French attempt to leave the path of budget rigor.

"Hollande believes there has been a turning of the tide, not only in France but in the eurozone, that he is more in tune with the zeitgeist, and that with a bit of luck Merkel will lose the next election and the left will once again be in power in Europe," said Nicholas Spiro of London-based Spiro Sovereign Strategy. "But that is a big gamble."

(Reporting by Geert De Clercq; Editing by Paul Taylor and Philippa Fletcher)