If you have been seeing me in discussions on this forum, you would know better than to question my german language skills, just saying 
So your answer to the very real issue of basically looking the other way and allowing certain crimes by certain ethnic groups go pretty much unchallenged/unopposed is to say "uh that's just how it is unless you want a police state?"
What nonsense. The police is actually doing a pretty good job fighting crime in all other areas as it is, EXCEPT in this area, because it is politically difficult to fight it the same way as all other crime is being fought. If you try, you run the immediate risk of being publically shamed as "nazi" and/or "islamophobe" on the one hand and on the other run the real risk of getting very real and very personal death threats to yourself and your family, by the group you are trying to police.
I am not saying that the experiences the authors describe didn't happen. What I am questioning however is whether or not these things are actually representative. Kambouri tells of her experiences as a beat cop, of incidents where immigrants, or people with an immigrant background, do not respect her or the uniform she wears. But she also (in an interview with the Frankfurter Allgemeine) says this:
„Meine Freundin und ich stehen für die große Mehrheit der Migranten und ihrer Kinder, die bestens integriert sind.“ Genau deshalb dürfe man nicht die Augen vor der Minderheit verschließen, die ganze Stadtteile terrorisiere. „Ich will ja genau das nicht: dass die Bevölkerung immer ausländerfeindlicher, rassistischer wird. Wir dürfen einfach nicht verschweigen, was die Realität ist, wir müssen klar und deutlich thematisieren, was die Probleme sind.“
Translation:
"My friend and I are representative of the vast majority of migrants and their children, who are fully integrated." That's why it would be wrong to turn a blind eye towards the minority terrorizing entire city districts. "This is exactly what I do not want: A populace that's getting ever more xenophobic, racist. We mustn't keep silent about what the realities are, we have to be clear in our discussions about what the problems are."
But then, if you look at the amazon reviews for her book, you will find several people saying that her account proves that integration has broadly failed, when that just isn't true. I am 100% with you that people who break our laws should be punished as appropriate. I disagree, however, with the notion that the behaviour of a tiny minority should be taken as any indication that everyone who shares that ethnicity is as incapable of living within this society.
That being said, you cannot stop the formation of small pockets of lawlessness in a country, unless you are willing to create a true panopticon society. Being shocked that they exist is a sign of naivete, in my opinion.
This is my main objection to maslo and Hornet and all the others who believe that closing our borders is the right thing to do. It's a blanket punishment for being born in a wrong place at a wrong time (and yes, I consider not being able to live where I choose a punishment, see Article 13 of the universal declaration of human rights), without any sort of consideration for the individual. Also note that freedom of movement is something the alien invaders currently running the show do not want us to have; it's one thing if capital is free to move, but granting laborers the same right means that there are fewer people around to do the cheap gruntwork.
There are lessons to be drawn from Paris and Cologne. But those lessons should not be "Immigrants are evil!", because that sort of sentiment never leads to anything good.
Furthermore, while I agree that it is on the immigrant to adapt to his or her new home and not the other way around, expecting or demanding that they'll immediately forsake every little bit of their culture is stupid. Cultures are always changing and that means that sometimes they're changing in ways we won't like, but you cannot demand that no change be allowed.
If you do speak German I dearly suggest you do read Kirsten Heisigs "Das Ende der Geduld". Kambouri is a more personal observation, but Heisig really lays down the facts and backs them up with statistics. Furthermore, Heisig gives a much more balanced overview of all kinds of crime including German youth crimes. Crimes committed by perpetrators of arab and turkish background are not really focused on specifically, yet are especially shocking because a) there is so much of it and b) due to the nature of the crimes.
The main problem is: Culture, in the case of criminal clan/families of mostly arab background directly conflicts with the law and the constitution, which is pretty much the basis of our society that allows us to live together peacefully.
So speak frankly please The E, what do you really want to do:
If you have to choose between the constitution, most specifically, between human dignity, freedom of speech and equality between men and women, heck even the right of physical integrity on the one hand ... and criminal clan structures that deny all those rights to their members and all citizens they come in contact with on the other, up to and including dropping rape charges because the victim would "lose her honor" if the "perpetrator" (her own father) would be accused and punished and hence the crime would become known to the whole family. And yes, this is a specific case, as quoted in Heisigs book, and that was not a justice of peace who spoke the verdict, but a german court, and you know why? Out of respect of the "culture" of the family in question. Because "culture" in this case would mean that if the crime got known, the victim (yes the victim) would be as good as dead. (Loss of honor usually leads to a honor killing, imagine that) and the German state taking away a child for her own protection ... from an arab family ... well imagine the press, can't do that, political correctness remember? So you are stuck with this mess.
If the same crime happened within any other ethnic community within Germany all hell would have broken lose and the child would have been protected by the youth wellfare office with the father facing a huge prison sentence and the media being all over it.
And that ... is a double standard that has now been established in the legal system out of pure political correctness and not wanting to "offend" their culture. If you haven't, please do read the book. The above was just one example out of a huge putrid mess of disgusting crimes that pretty much can only be committed in the way they are, because police and the legal system are deliberately looking the other way out of political correctness.
Don't take me wrong. I totally agree with you on this: Definitely not all refugees are like this. Quite the contrary, a lot of them are outraged about this just the same as any German is and what they do not understand is, why the German state does not do something about it. Yes, moderate muslims, turks, and refugees are all shaking their head in disbelief. Mind you ... Heisigs book and the case above is over 5 years old and concerns immigrants that live here in the 2nd and 3rd generation already (and yes, three generations, without integrating one inch at all - that alone a fead not one other ethnic group has managed.). Things have not improved. And decent refugees arriving now and see this mess can't understand it anymore than anyone of us can.
So if you defend "culture" just because of "culture" unilaterally ... what you effectively do is legitimize rape, murder and organized crime. That's how it is, so no sir, you can't have your cake and eat it too. If you try to paint this black and white you simply do not understand the issue. It's NOT black and white. Culture is NOT always good. And you know when it isn't? When it is dehumanizing. When it is a culture of hate. A Culture of racism. A culture of bigotry. A culture of misogyny. A culture in outright disrespect to civilization itself. A culture unchanged from the dark ages up to today. ... And yes ... you have all of that, organized and strong, in the middle of Germany, within the borders of major cities right now, not because you can't do something about it, but specifically because everyone including the police and legal system are worried about it not being "politically correct" to do something about it.
Be careful what are unsuspectingly defending here.