Berlin is a destination for many immigrants from all over the world; this is the reason that makes it one of the most multicultural cities in Europe.
Maybe too multicultural.
Summing immigrants and children of immigrants today are presumed about one million immigrants, nearly a third of the population; and this would not be a problem if they could integrate.
But integration is sometimes a natural process and other times it’s just hard, the fact is that almost always people prevenient from other countries tend to aggregate with each other, rather than open up to the german culture, language and customs.
Although the government encourage and offers many free courses for integration, including basic knowledge of the language, the rules to work, and lots of useful information for life in Berlin, and in Germany, there are some areas of the city where the presence Germans is zero; and, like a dog chasing its tail, it doesn’t help, instead makes it even more complex than it should be substantially natural: acquire the new culture of the place with a two-way exchange.