"Among other things, prospective citizens must take 650 hours of language instruction as well as demonstrate knowledge of the German constitution... More importantly, in order for Turks to naturalize they must demonstrate that they have renounced their Turkish citizenship, and since 2000 they must sign a document stating that they will not acquire a second citizenship. If they do acquire a second citizenship, they immediately lose their German one. Before 2000, many Turks, when they renounced their Turkish citizenship, were told by the Turkish embassy that they could reacquire Turkish citizenship after they obtained their German citizenship."
"The German government, in the context of highly politicized elections, however, has begun to enforce the denaturalization of those Turks who reacquired Turkish citizenship, and it is estimated that approximately 50,000 Turks have lost their German citizenship."
Even these requirements are considered liberal for them.
There's nothing more permanent then temporary workers.
And you know how the Swiss recently voted.