Le Pen’s polls have looked good in other elections, but in the past, when the voters actually go to the polls, the votes don’t reflect it. Hopefully this time it will be different.
It’s because there has been a stigma, and rightfully so, surrounding the National Front party and it founder, Jean Marie-Le Pen. He is notorious for advocating denialism regarding the Holocaust. (Hence Marion Marechal’s attempts to rebrand the party moving forward and changing her name.)
France has a notorious anti-Semitism problem in general...it’s one of the things holding the country back from renewal. This preceded the Islam/migrant crisis.