Twitter users turned Sunday's French presidential election into a battle between a green Hungarian wine and a red Dutch cheese in a bid to get round tough laws banning result predictions.

The #RadioLondres hashtag was the top France trend on Twitter during the first-round presidential vote, in homage to World War II codes broadcast to Resistance fighters in Nazi-occupied France from the BBC in London.

But French citizens have written a new codebook in a subversive bid to get round laws that mean anyone announcing vote predictions before polls closed at 8:00 pm (1800 GMT) could be fined up to 75,000 euros (100,000 dollars).

"Tune in to #RadioLondres so as not to know the figures we don't want to know before 8:00 pm," said one ironic tweet.

As a result, incumbent Nicolas Sarkozy became either Tokaji wine which, like his father, comes from Hungary, or Rolex because of his perceived "bling-bling" lifestyle.

His Socialist opponent Francois Hollande was either Gouda cheese (from Holland) or a soft, sweet "Flanby" caramel desert -- an old and unforgiving nickname for the portly frontrunner.

Far-right candidate Marine Le Pen was associated with the names of totalitarian regimes or rodents and Communist Party-backed Jean-Luc Melenchon was either a rotten tomato or something linked to the former Soviet Union.

The tweets were witty, bemused or cruel, with many including links to francophone media websites in Belgium or Switzerland that are beyond the reach of French law and thus able to publish leaked estimates.

"Dutch cheese at 27 euros, Tokai wine at 25 euros," read one tweet as poll percentage predictions were published abroad.

"This Belgian site has excellent weather forecasts," said another.

"The sea temperature is 16 degrees. Global warming is indeed happening," said one tweet, in a reference to the score of the far-right candidate's first name, Marine.

"Who's doing the 75,000 euro tweet then?" said one tweet. With only 10 French election officials reportedly tasked with monitoring social networks for breaches of the law, web users felt free to enjoy themselves.

"Previous election evenings were not so fun, thanks," read a tweet grateful for the light relief during the tense election today.

"It has snowed on the mountaintops, I repeat, it has snowed on the mountaintops," said one of the more enigmatic tweets, echoing the apparently incomprehensible coded phrases broadcast by the French during World War II.

Other remarks made digs at Sarkozy's stature as it emerged that he would not win the vote, saying that "high-heeled shoes are going out of fashion".

"#RadioLondres Twitter is stronger than you, broadcasting commission" said another tweet, mocking the body that monitors the application of election laws on broadcast media and the Internet.

The huge outpouring of frustration with laws many consider outdated in an age of instant, global communication led one Twitter user to note: "It's incredible what this hashtag betrays about the state of mind in France."

Late Sunday, the head of France's polling commission, Jean-Francois Pillon, said he would ask the prosecutor to draw up charges against "individuals and media organisations" who allegedly broke the law.

"There are acts that appear to us to be punishable," he told AFP.