The hastily assembled Popular Front (NFP) - spearheaded by left-wingers including former Presidential candidate Jean-Luc Melenchon - is pledging to increase public spending by £125 billion if they successfully form a government.
They have also proposed a 90 percent tax on incomes over £340,000 a year - but Mr Le Maire suggests such a move could cost more than £250 billion with France already saddled with a budget defunct of 5.5 percent.
The Finance Minister explained: "The most immediate risk is a financial crisis and France's economic decline.
Speaking on the political situation, UK-based banking expert Bob Lyddon has told Express.co.uk the result signals an end to Emmanuel Macron's policy of "controlling debt and public spending", warning the inevitable "deadlock" is** no better than a victory for Marine Le Pen's far-right National Rally.**
France and England are going to have a period like our last 3.5 years. But I think it will be a little shorter, but far more intense. It is harder to wake those people up.