Monsieur Le Commandant

This book is about a French soldier that is writing a letter to a local SS officer.
The letter is split up into chapters to make it easier to read.
I don't particularly like the person Paul-Jean Husson who is writing to the SS officer, he is a fascist, and a pervert, his son Olivier is married to a German-Jewish woman named Ilse but he doesn't find out till later that she is Jewish.
He hates the Jewish people, and believes that they are turning France in 1940-1945 into a “cesspool” due to foreign people in his country his “motherland” and something must be done about the “Jewish problem or the Jewish question” as it was referred to in the book.
I do not share this opinion and I haven't read much about this era in time yet, but I don't understand why they condemned the Jewish people just due to their race and nationality or because they didn't like the way they worshiped god, because they are christian.
Paul-Jean is lusting after and in love with his son's wife, who is only 19 and he is old enough to be her father which is disgusting, but eventually he manipulates the situation so they are intimate and she becomes pregnant with his child and was considering getting rid of it because it is suspicious why she is pregnant again after, having two of Olivier's children Hermione and Aristide so she thought it was a “silly or stupid mistake” and wouldn't speak to him afterwards because she was ashamed and didn't want Olivier to find out.
Since she was a German she married Olivier and he insisted on her becoming a French citizen so no one would suspect anything and Paul-Jean asked people that he knew to hide her documents so they wouldn't look any further in her background and find out that her religion was Jewish.
However even though the “naturalization process” whatever that is I don't really understand what it is and what the Germans did to “naturalize the Jews”
She was still questioned by the authorities and sent to a concentration camp where she died.
I think due to her thinking that it was a mistake that Paul-Jean Husson told the authorities that she was a Jew and that's why she was sent to Auschwitz and died, because that is exactly what happened to her, while still pregnant she was murdered by the Nazis!
He said “he still loved her and he also said that he hated the Jews” Ilse was Jewish so she was already doomed to die sadly.