Those results are not so surprising if you look at facts. The basics are simple: average people are fed up with the never-ending decrease in the standards of living, and so lash at the establishment they know is the reason behind this fall (all those people who benefit from Globalism and keep repeating Thatcher’s ‘There is No Alternative’).
In Europe, the Establishment uses the EU to slowly attack and destroy every progressive achievements made ever since WWII. As such, the Brexit (despite all the Remainers who keep screaming the first reason is racism. News flash, people tend to reject anything and anyone even slightly different when the economy makes them feel threatened in their very lives).
In France, Hollande was elected on an agenda that was, essentially, ‘take down the bankers’ privileges, loosen the stranglehold the stockmarket has on the Economy’. Instead of even attempting to do that, from day one he simply just threw every single one of his promises into the bin and essentially did what Sarkozy would have done. So much for the idea of a difference between the two main parties (PS and LR, previously UMP, previously RPR).
At the same time, here was Le Pen’s Front National. Important point: this party is, essentially, a family business. The founder, JM Le Pen (father of Marine), never had any wish to be elected. He simply liked receiving money from the state (which all parties getting over 5% do), and having a cushy ‘job’ as an European MP. However in 2007, Sarkozy managed to attract many of its voters, making it lose quite a lot of money.
Enters Marine.
Contrary to her father, she has apparently started to believe in her chances to win the elections. And so she rebuilt her party’s image around two points: the FN was an outsider, and they didn’t want the EU (analysing that people hadn’t forgotten the NO to the 2005 EU referendum that was completely ignored by Sarkozy and Hollande in 2007-2008 with the Lisbon treaty). She was helped by both the media (who like juicy pieces of news) and the two main parties, especially the PS, as they saw the FN as a very nice way to make people vote the way they wanted, i.e. for the PS and none of the left alternatives (for fear of a repeat of 2002 which saw Chirac against a very surprised and unprepared Le Pen). Indeed it worked in 2012, with many on the Left voting for Hollande to make sure he would go on to the second round.
This is not going to happen this time. It’s pretty much the only case where Le Pen could win, if she were to face Hollande (he is that hated, a bit like Clinton).