The far-left candidate wasn't a well-known figure outside France, but his recent surge in opinion polls raised eyebrows among investors and commentators. If Melenchon were to advance to the runoff, France could be faced with a final choice between the far-right and the far-left.
Pierre Gattaz, leader of France's main business lobby Medef, described such a scenario as "a catastrophe" and a choice between "economic disaster and economic chaos." Melenchon has pledged to raise public-sector wages and take on more debt to subsidize that. When it comes to Europe, his views are similar to Le Pen's. He wants a renegotiation of European treaties and if the EU weren't to agree, he would quit the Union.
The head of La France insoumise (Unsubmissive France) is tied with Fillon in the latest polls with 19 percent.