Though some commentators see Melenchon‘s challenge as a blip that may fade, his rise has injected further uncertainty into the outcome of the race for the Elysee, in which Macron has largely been seen as the favorite.

Some investors are even weighing up the possibility of Melenchon making it into the second round against Le Pen, a clash between two far-left and far-right arch-rivals that would stand French politics on its head.