I don't know what she means, only what she said. She did not say what those areas were, how many, how large, how they were created, who to blame, etc. Her focus seems to be from the federal level there needs to be some direction and standardization. In Germany, law enforcement is a state level responsibility. They do have a national police force, but the Bundespolizei have limited domain somewhat like the RCMP in Canada. They may patrol airports like Canada, and in Germany the railways are federal so they are policed by the federal force, but roads and the rest of the public space is the responsibility of the state level forces.

The fact that even Germany's government officials  have been "left speechless" by her admission - means, that's what it means  - a referral to what others have been saying regarding Muslims, to be specific.

http://abcnews.go.com/International/wireStory/merkel-germany-areas-govt-53416102

What else is a "no-go zone" when we talk about places like Germany?  

And the truth is there isn't it, I know people in the U.K. who say the same thing but it's not admitted, they just call them 'problematic areas'.