Unease at Le Pen's strong showing in France's presidential race has hurt French government bonds in recent weeks, with her anti-euro stance unnerving investors.
She is accused of having barely worked for the salary. They are campaigning hysterically for their darling.
Polls have always shown either Macron or the other likely second-round challenger François Fillon of the Republicans beating Le Pen in the run-off.
Analysts urge caution about making firm forecasts, however, after a series of political shocks in Western democracies in the a year ago and a string of surprises in French politics.
Macron has been lifted in polls by the alliance with centrist Francois Bayrou, leader of the MoDem party.
The ex-banker, who started his own political movement En Marche (On The Move) last April, has also started giving more details of his pro-business platform ahead of the official launch of his program on Thursday.
Both Fillon and Le Pen have also attacked judicial investigations into their use of allegedly fake parliamentary aides as an attempt by outgoing Socialist President Francois Hollande to influence the election.
Some 2,200 demonstrators are estimated to have gathered in central Nantes to protest against Le Pen who is coming for a campaign rally ahead of this spring's presidential election. However, his campaign as faltered in the wake of allegations that he had paid his wife Penelope at least €650,000 of public funds for a suspected fake parliamentary assistant job spanning 15 years.
They both deny wrongdoing and claim the investigations are politically motivated.
In one passage she targeted what some observers see as his vulnerabilities, namely his pro-European sympathies at a time of widespread disaffection with the European Union project, as well as his openness to immigration.
Macron scored another victory this weekend with the announcement that he will meet with German Chancellor Angela Merkel in mid March. "We will never bow to seeing militias of the far left wrecking, burning and attack the physical integrity of the police as yesterday in Nantes with the more or less obvious complicity of the government", she said.
Another former premier, the Socialist Manuel Valls, has also warned of the "danger" of assuming that Ms Le Pen can not win.