The right wing leader of National Front has crept ahead of Emmanuel Macron and Francois Fillon, the latest polls have shown.
Ms Le Pen is tipped to get 26 per cent in the first round of voting in the French election, with Mr Macron taking 21 per cent and Mr Fillon 20.
Despite doubts Ms Le Pen could win her support is growing, especially from working class voters where she has around 44 per cent.
Loyal Le Pen fans are most likely to stick with their decision, polls suggest, with others being more likely to swing their vote.
Three quarters of voters for Ms Le Pen say they will vote for her no matter what, but only a third for Mr Macron’s fans said the same, and 60 per cent of those who are voting for Mr Fillon said they will not be swayed.
Ms Le Pen is hugely popular among workers in France, especially with policies which say foreign workers will be taxed more to pay for the unemployed in her country.
Polls say Ms Le Pen will likely win the first round but will not bee elected in the second.
Mr Macron is seen as being able to beat Ms Le Pen in run-off vote by 62 per cent to 38 per cent.
Mr Fillon would beat Ms Le Pen in run-off vote by 57 per cent to 43 per cent if Fillon made it through to second round, polls say.
The overall winner will need more than 50 per cent of the vote to become president, taking the helm from Francois Hollande.
However, pollsters failed to predicted Brexit and the Trump election which has failed to inspire confidence in their results.