Le Pen, speaking at a rally in the western city of Nantes, launched a series of attacks on the 39-year-old independent who has emerged as a frontrunner to become France's next leader.
She accused the ex-economy minister of wanting to create a "migrant motorway" between France and north Africa, adding that "financial interests and their intermediaries in the media" had clearly taken his side.
In an attack that recalled US President Donald Trump's confrontation with journalists, she added: "The media have chosen their candidate. They are campaigning hysterically for their darling.
Two new polls published today showed Le Pen still winning the first round of the election on April 23 with 27 per cent, but Macron closing the gap on her with 25 per cent.
More From This Section
In the run-off vote set for May 7, despite her belief that Trump's victory and Brexit point to a revival of nationalism and anti-elite movements like hers, Le Pen would lose by 20 points to Macron if it were held today, the polls suggested.
The new polling was done immediately after Macron sealed an electoral alliance with fellow centrist Francois Bayrou last Wednesday -- removing a potential rival just as increasing numbers of backers from the Socialist party and the centre-right are also trickling in.
Communist-backed candidate Jean-Luc Melenchon meanwhile ruled out striking a similar deal with Socialist Benoit Hamon, which the French left had hoped could allow them to mount a serious challenge.
"He confirmed to me what I already knew, which is that he is running," Hamon told TF1 television tonight, announcing the setback after managing to secure a tie-up with environmentalist candidate Yannick Jadot.
On the right, Le Pen and Republicans party candidate Francois Fillon have become increasingly embroiled in legal problems.