Well, the Turks and German-Turks in Germany are worker class or unemployed.
It's an often denied fact, but they are in competition with the German worker class and unemployed workers for jobs. The social situation also causes unfavourable criminal statistics and low respect of middle and upper classes.
That's not helpful.

Another aspect is that the Turkish culture is quite different, especially the very backward version that's in use with the emigrants (who often stick to a culture as of 1950's rural Turkey). They provide occasionally terrible examples (like murder of sister because she was too Western and 'dishonoured' the family and such nonsense).

Finally we have some really stupid newspapers in both languages.

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About racism and national conflicts in Germany in general:
There's no real "racism" in Germany. It's rather an antipathy towards specific nationalities.

positive:
UK
Scandinavian countries
France (although they're not particularly friendly to us)
Spain & Portugal
Italy
Austria & Switzerland (they speak German...kind of)
Australia & New Zealand
Canada
Asians (India to Japan)
Netherlands (although they dislike us)

divided:
Poland (hard-working helpers in agriculture and grey market in general, but also notorious for stealing cars)
USA (this goes to negative for sure if McCain gets elected)
Russia ("drunk")
Arabs (quickly drifting to negative due to corruption and extremists)

neutral:
Bulgaria
Slovakia
Czech
Belgium
Latin Americans
most non-Russian Eastern Europeans
most Africans
Carribbean countries

negative:
Romania (Romanian gangs had serious looting campaigns in Germany in the early 90's. They crashed into stores, about 10 Romanians stole as much as possible and loaded the truck, then they drove to next town. Seriously.)
Ghana (quite many Africans sitting unemployed in cities and supposedly dealing drugs - many of them are assumed to be from Ghana for some unknown reason)
Afghans (drug troubles)
Vietnamese (cigarette smuggling, most of them are a leftover of DDR friendship policy with Vietnam in 70's and 80's)
Albania (lots of very violent criminals)
Turkey (mentioned above)

An American black man would feel next to no discrimination in office clothes in Germany, but if misunderstood for a Ghanaan seeking asylum he might run into troubles monthly.
A Romanian would be under close scrutiny, a Bulgarian likely not.
A Macedonian would have little if any troubles (I had a Macedonian friend and he never had serious problems), but an Albanian would likely get no job.
Skin colour and religions are quite unimportant, nationality is much more important in Germany.