Reading suggestions for Mélenchon on areas of similarity

Jean-Luc Mélenchon, the defeated candidate of the far left in the first round of the French presidential election is indifferent between Marine Le Pen and Emmanuel Macron. During the campaign for the first round, he campaigned on the promise of leaving the EU if the institution did not reform along the lines proposed by himself. Like Californian secessionists, his idea of a shared democratic institution is to leave it if he cannot impose his program. This is paradoxical for a left wing candidate that supposedly bases his ideology on solidarity, as very well explained in an article in The Nation that criticizes Californian secessionists. Now he is undecided between a Holocaust quasi-negationist and a pro-European candidate. Warnings from history are necessary, which is why Mr. Mélenchon perhaps would find useful to read two reviews of a recent biography of Hitler, one in The Nation and another one in The New York Review of Books. These reviews make clear that no contemporary politician is like Hitler, but they also make clear that the past provides useful lessons. National-populists look ofended when they are compared with past fascists, but careful historians in serious publications do not shy away from making the comparison, starting with the obvious point that nothing is like Hitler. This is Cristopher Browning in NYRB:
"When the original German edition of Volker Ullrich’s new biography, Hitler: Ascent 1889–1939, was published in 2013, the current political situation in the United States was not remotely conceivable. The reception of a book often transcends the author’s intentions and the circumstances in which it was written, of course, but rarely so dramatically as in this case. In early 2017 it is impossible for an American to read the newly published English translation of this book outside the shadow cast by our new president.
To begin I would stipulate emphatically that Trump is not Hitler and the American Republic in the early twenty-first century is not Weimar. There are many stark differences between both the men and the historical conditions in which they ascended to power. Nonetheless there are sufficient areas of similarity in some regards to make the book chilling and insightful reading about not just the past but also the present."