(This April 2 story was refiled to add Russia Today's denial in paragraph 18)
By Richard Balmforth and Michel Rose
PARIS (Reuters) - France's polling commission has issued a warning over a Russian news report suggesting conservative candidate Francois Fillon leads the race for the presidency - something which contradicts the findings of mainstream opinion pollsters.
The cautionary note from the watchdog on pre-election polling followed allegations in February by aides of centrist candidate Emmanuel Macron that he was a target of "fake news" put out by Russian media including the Sputnik news agency.
Macron takes a hard line on European Union sanctions imposed on Moscow over the Ukraine crisis, whereas Fillon has said they are totally ineffective, creating a "cold war" climate that needs to be reversed.
Almost all media in France are drawing on polls that have shown since mid-February that Fillon, a former prime minister, is trailing in third place behind Macron and far right leader Marine Le Pen for the April 23 first round. Third place would mean Fillon's elimination from the May 7 runoff.
State-run Sputnik carried different findings in a report on March 29 under the headline: "2017 presidential elections: the return of Fillon at the head of the polls".
It quoted Moscow-based Brand Analytics, an online audience research firm, as saying that its study based on an analysis of French social media put Fillon out in front.
In a statement, France's polling commission said the study could not be described as representative of public opinion and Sputnik had improperly called it a "poll", as defined by law in France
"It is imperative that publication of this type of survey be treated with caution so that public opinion is aware of its non-representative nature," it said.
Brand Analytics' track record either for political polling or for commercial internet audience measurement outside of Russia and former Soviet territory is unknown.
Sputnik published an earlier online survey by the firm from mid-February which also showed Fillon with a strong lead over Macron and Le Pen at a time when other polls showed Macron’s candidacy beginning to surge with Fillon in third place.
Neither Sputnik in Moscow, nor the company, responded immediately to emailed requests for comment on Sunday.
U.S. INTELLIGENCE WARNS
Richard Burr, head of the U.S. Senate Intelligence Committee which is investigating the Russian hacking during the 2016 U.S. presidential campaign, said last week that the Kremlin was trying to interfere in the French vote.
The Kremlin denied in February that it was behind media and internet attacks on Macron's campaign.
Russia has a strong interest in the outcome of the French election since Macron has suggested imposing further sanctions on Moscow if it does not implement its side of a deal to resolve the crisis in Ukraine.
Fillon, once the frontrunner for the Elysee before he was hit by a scandal surrounding payments of public funds to his wife and children, dismissed as "fantasy" concerns of Russian interference in the election. Speaking last Friday, Fillon said he would seek a better balance in relations with a country that was nevertheless "dangerous".
Richard Ferrand, the head of Macron's En Marche! (Onwards!) party, said in February that Sputnik and another Russian state-run outlet Russia Today were spreading 'fake news' with the aim of swinging public opinion against Macron.
Russia Today, in a statement, said that it rejected any suggestion that it was part of spreading fake news in relation to Macron and the French election.
In February, Sputnik announced it would publish weekly French election polls using representative sampling from three mainstream polling firms - IFOP, Ipsos and OpinionWay - alongside an analysis of social media posts in France from Brand Analytics for which it did not disclose its survey methodology.
Separately, Sputnik carried a news report last Friday about Macron supporters being awarded state decorations when he had been a high-level functionary at the Elysee and economy minister in the Socialist government, suggesting this could amount to influence peddling.
It offered no proof that Macron had organized the decorations, which were sometimes awarded by other ministers. In several instances, it cited awards made by the economy ministry, without mentioning that Arnaud Montebourg, Macron's predecessor, was minister at the time.
The Sputnik report contrasted Macron's alleged action with a judicial inquiry into an award made when Fillon was prime minister to a billionaire friend who owned a cultural magazine where Fillon's wife drew a salary.
(Additional reporting by Michel Rose, Eric Auchard and Vladimir Soldatkin; Writing by Richard Balmforth; editing by)