On a visit to eastern France, Mr Macron was confronted by a voter who said: “I have never seen a more rubbish president. You are a Machiavellian manipulator.”
It came as the French President accused Ms Le Pen of talking “rubbish” about Brussels.
Mr Macron even said his rival has a secret plan to drive France out of the EU but did not dare tell voters, also accusing her of extremism, dishonesty and cowardice.
He warned Ms Le Pen would follow David Cameron’s example, predicting a “Frexit” move if she were to become President.
The 44-year-old said: “This election is a referendum on Europe.”
Emmanuel Macron PIROSCHKA VAN DE WOUW
Marine Le Pen Charles Platiau
He went on to describe the EU as a “treasure” that had preserved peace on the continent and helped France through the Covid crisis.
Mr Macron, who is the clear favourite in the French presidential race, continued: “Europe is a space of peace, culture and democratic values but it is threatened.”
He said Ms Le Pen’s policies were based on nationalism and “nationalism is war” before claiming that France would become like Hungary if she came to power, where “rights are meticulously and progressively reduced”.
Ms Le Pen once said she wanted France to follow Britain out of the EU but now insists she wants to reform the bloc from within and reduce the French financial contribution.
Hitting back, Mr Macron said: “Marine Le Pen is talking rubbish when she says would not pay [the EU’s] bills and that she will change the rules on her own.”
He added: “[Ms Le Pen] wants to leave but she does not dare say so. That’s never good.
“She says she wants an alliance of nation-states but she is going to find herself in a corner and she is going to try to come up with an alliance with her friends.”