Macron's spokesman Benjamin Griveaux accused the Kremlin of mounting a "smear campaign" via state media against the 39-year-old centrist former economy minister.
Macron's spokesman Benjamin Griveaux accused the Kremlin of mounting a "smear campaign" via state media against the 39-year-old centrist former economy minister, a staunch defender of the European Union who is riding high in polls.
"The Kremlin has chosen its candidates: Francois Fillon and Marine Le Pen," Griveaux told the broadcaster i-Tele, referring to the conservative Republicans candidate who is pushing for closer ties with Moscow, and the leader of the anti-immigration, anti-EU National Front.
Russia's choice was "for a very simple reason: they do not want a strong Europe, they want a weak Europe," he alleged.
Griveaux accused the state-owned Russia Today (RT) channel and the Sputnik news agency, both of which have French-language sites, of trying to taint Macron, who was forced last week to deny rumours of a gay affair.
The claims echo accusations by US officials that Russian President Vladimir Putin ordered cyberattacks on US organisations to help Donald Trump get elected.
Moscow vehemently denied the French allegations.
"We never had, and do not have, the intention of interfering in the domestic affairs of other countries, and especially not in their electoral process," Kremlin spokesman Dmitry Peskov said.
RT and Sputnik echoed the denials.
The allegations came as a poll showed Macron's campaign stagnating for the first time in weeks.
The Opinionway poll showed Le Pen stretching her lead in the first round of the election in April to 27 percent compared to 22 percent for Macron.
While Macron was shown easily beating her in a May runoff between the top two candidates, former frontrunner Fillon, who is battling an expenses scandal, appeared to halted his slide, gaining one point to 20 percent in the first round.
Fillon has been dogged by revelations that his Welsh-born wife Penelope was paid for years for a suspected fake job as a parliamentary aide. He insists she played a real role.
On Tuesday, he faced down another attempted putsch from within his party, telling Republicans lawmakers there was no question of him stepping aside after winning November's rightwing primary.
A day earlier, a group of around 20 MPs from the party has said they could no longer bring themselves to campaign on his behalf.
Those present at Tuesday's meeting however said the "vast majority" of the party's MPs had reiterated their support for the 62-year-old former premier.
Rumours about Macron's private life had grown louder in recent weeks, in tandem with his poll surge.
Last week, he tackled the gossip head on, laughing off claims he was cheating on his wife with the head of French radio, Mathieu Gallet.
In an opinion piece in the daily Le Monde on Tuesday headlined "Russia must not be allowed to destabilise the French presidential election", the secretary-general of Macron's movement En Marche (On The Move) accused RT and Sputnik of fanning the "slanderous" claims.
"One day he is being financed by 'a rich gay lobby', the next he is an 'American agent of the banking lobby'," Richard Ferrand wrote, referencing claims by a lawmaker from Fillon's party published by Sputnik.
Griveaux on Tuesday also pointed a finger at Russia over a flurry of cyberattacks on Macron's campaign site in the past month.
"Half of the attacks, and there are hundreds a day, come from Ukraine, which is known for its links to hackers and people responsible for cyberattacks in Russia," he said.
During a visit to Algeria on Tuesday Macron said he welcomed Russia's assurances of neutrality.
"They should pass on the message to Russian media not to relay false rumours," he told AFP, adding that he would remain "vigilant".