PARIS (Reuters) - Benoit Hamon has an enticing offer for French voters if elected president in May: his Socialist government would give each and every one a regular wage, whether they work or not, be they billionaires or paupers.

Former French education minister Benoit Hamon reacts after partial results in the second round of the French left's presidential primary election in Paris, France, January 29, 2017. REUTERS/Christian Hartmann -

Alongside promises to legalize cannabis, abandon diesel fuel and cancel debts between European Union countries, Hamon, the ruling Socialist Party’s candidate pledges a “universal income” for all citizens.

The cost, says the 49-year-old, will be around 350 billion euros ($374.82 billion), roughly equivalent to the annual budget of Europe’s second-biggest economy. An ambitious overhaul of taxes will be pursued to fund it, he says.

The idea has captured the imagination of Socialists who feel betrayed by a shift to more pro-business policies under President Francois Hollande and Manuel Valls, the former prime minister whom Hamon beat on Sunday to win the left’s presidential ticket.

Hamon’s win, with over 58 percent of the vote according to partial results on Sunday evening, is yet another upset in an unpredictable presidential race.

He was until earlier this month one of several outsiders in a party contest that Valls, a more moderate and more experienced leader, was initially predicted to win.

Valls labeled Hamon “the sandman”, a seller of dreams which would condemn the Socialist Party to an opposition role for years to come. Valls readily compared his rival Jeremy Corbyn, leader of Britain’s main opposition Labour Party.

But while Valls struggled to shake off the tag of prime minister to the deeply unpopular Hollande, Hamon struck a chord with left-wing voters by declaring on the campaign trail: “I am running for president so that France’s heart will beat once again.”

Hamon’s most visible public roles were as Hollande’s junior minister for the social economy and later as education minister. He quit that post in protest at what he viewed as the party’s shift towards the political right and big business.

ROBOTS VS WORKERS

His campaign platform, he says, is based on his conviction that jobs are scarce and will become more so as a digital revolution takes hold and leaves workers displaced by self-driving cars, drones and robots.

Society will only adapt if it accepts that people work less and jobs are shared across a greater number of workers, Hamon says - hence his proposals of a shorter working week and a basic income of 750 euros a month for all adult citizens, whether they work or not.

“Look at Germany, model country with full employment, where the jobless rate is five or six percent. Nobody sees the poverty rate is 17 percent. In reality, it’s a tradeoff: jobs at the price of poverty,” Hamon said at a meeting in Marseille.

Hamon acknowledges his proposal will require a major revamp of taxes. Among other fiscal policy promises, he plans a “robot tax” levied on the profit margins of digital industry groups as well as higher taxes on giants like Google and Apple.

Like other hardline French left-wingers, Hamon says Hollande eroded the spending power of the working class. He wants to raise the minimum wage, currently about 1,150 euros a month, by 10 percent and raise civil service salaries too.

But unlike some other staunch socialists, Hamon defends the European Union, at least in as far as the bloc could help reduce tax competition between member states and equip Europe for trade competition with the United States and China.

Euro zone rules on budget restraint should however be suspended pending changes that would allow for increased spending on defense and policing to fight terrorism.

He proposes a near doubling of the defense budget to three percent of GDP, the hiring of thousands more police, and advocates the creation of a cross-border intelligence agency.

Asked if he was a dreamer, Hamon argued that France had lost its way and borrowed a line from Italian Marxist thinker Antonio Gramsci: “The crisis consists precisely in the fact that the old is dying and the new cannot be born.”

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