France's Left Bank intellectuals have long demanded a ban on advertising on state television, to turn public service broadcasters into a Gallic version of the BBC.

Yet, when President Sarkozy backed their calls with a surprise announcement that commercials would end on France Télévisions next year, they reacted with horror.

Some detected a covert plot to underfund and then break up the public group. Others suspected that Mr Sarkozy was offering a sly present to private channels, which would pick up advertising revenue.

Alain Duault, a television presenter, reacted angrily to the conspiracy theories. “The apostles who had been advocating this measure for years now say it's impossible,” he said. “It's a bad idea in their eyes simply because it is Nicolas Sarkozy who is putting it forward. What hypocrisy.”

The President caught analysts, commentators and most of his own ministers off guard when he decreed that the five channels that make up France Télévisions would be financed entirely by taxpayers from next January. Advertising has provided some revenue since 1968, and almost half of it in recent years.

Describing the move as “a real cultural revolution”, Mr Sarkozy said: “No one will be able to use the excuse which consists of saying, 'The tyranny of viewing figures stops me from having programmes adapted to public service broadcasting'.”

The President's advisers said he wanted a French BBC - despite the debate in Britain over its dependence on the licence fee.

François Fillon, the Prime Minister, said public service broadcasters should offer “cultural, educational and informative programmes” and added: “There is no reason to pay a licence fee to watch programmes which are identical to those on private channels.”

If Mr Sarkozy hoped to win cross-party support for his measure, he was soon disappointed.

“Why are we not applauding?” said Jérôme Bourdon, a media historian. “Quite simply because we have to think first and foremost in terms of resources.”

France Télévisions earned €835 million (£624 million) from advertising revenue in 2006, about 40 per cent of its income. The Government has pledged to make up the shortfall through state funding, but television executives are sceptical after Mr Sarkozy ruled out an increase in the annual €116 licence fee.

Instead, he wants to generate money through new taxes on advertising revenue on private channels and on purchases of televisions, computers and mobiles.

Both proposals were greeted with fury. The Union of Audiovisual Electronic Industries described the levy, which would hit its members, as “unfair, contradictory and inefficient”. It accused the Government of taxing the new media to fund the old, at the risk of propelling France backwards.

A 1 per cent tax - the rate suggested by Christine Albanel, the Culture Minister - would add up to €30 to the price of a flat-screen television, detractors said. But it would generate only about €300 million for the Government - less than half of what France Télévisions needs.

France's private channels are also lobbying hard against the planned new tax on advertising revenue, although they have much to gain from Mr Sarkozy's reform.

TF1, France's biggest private channel, for example, will pick up an extra €165 million in revenue when advertisers switch away from France Télévisions, according to one study. M6, the second biggest private channel, should reap €44 million. The rest will be split between cable and satellite channels, radio stations and internet access providers.

Mr Sarkozy's opponents, such as Patrick Bloche, a Socialist MP, pointed out that the President's friends would be among the beneficiaries. Martin Bouygues, for instance, the chairman of Bouygues, the construction group that owns TF1, is the godfather of Louis Sarkozy, the President's ten-year-old son.

“It's the consumer ... who will have to finance this present to the President's pals,” Mr Bloche said, apparently forgetting that his own party has often called for an end to advertising on state television.

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