French President Emmanuel Macron responded to allegations by Polish Prime Minister Mateusz Morawiecki on Wednesday with a rejection.
As the Elysée Palace announced, the allegations were "unacceptable".
Morawiecki had criticized Macron for maintaining dialogue with Russian President Vladimir Putin.
“President Macron, how many times have you negotiated with Putin?
What have you achieved?” said Morawiecki.
"Would you negotiate with Hitler, with Stalin, with Pol Pot?" asked the Polish head of government in a speech in Kraków on Tuesday.
Michael Wiegel
Political correspondent based in Paris.
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In the Elysée Palace, the criticism from Warsaw was seen as covert campaign support for Marine Le Pen.
Morawiecki was said to be Le Pen's ally.
Both politicians signed a call for a “Europe of fatherlands” last December.
At the "Warsaw Summit", 16 parties agreed to act more jointly in the EU Parliament.
Morawiecki raved about a "turning point in the history of Europe".
Le Pen had previously backed him in the legal dispute with the EU.
If she were elected France's new president in April, she would put pressure on the European Commission to release Poland's funds, Le Pen recently told the Polish newspaper Rzeczpospolita.
At the same time, Le Pen maintained close contact with Putin for a long time and posed with the Kremlin boss in 2017.
To this day, Le Pen is sticking to her election platform, according to which Russia is a security policy partner.
Morawiecki remained silent about Le Pen's ties to Putin, instead attacking Macron's telephone diplomacy with Moscow.
According to the Elysee Palace, Macron has spoken to Putin at least 16 times since the beginning of the year.
Morawiecki lamented the lack of results and called for Putin's war machine to finally be brought to a standstill.
The allegations from Warsaw are not new.
A year ago, the Polish Foreign Minister described France as “Russia's Trojan horse in the EU”.