Different person here.
From the interview https://www.morgenweb.de/sie-konnen-es-nicht-lassen-1.262032...:
>What happens, when a refugee climbs over the fence?
>Petry: Then the police have to stop the refugee from entering German ground.
>And if he is doing it anyway?
>Petry: You want to lead me into a specific direction.
>Again: What should the policeman do in this case?
>Petry: He must stop the illegal border crossing, using his firearm if necessary. [Note: The translation "if necessary" is maybe a bit off, can't find a better phrasing. The original sounds like you'd use it in less cases than "if necessary".] That's what the law says.
>There is a law in Germany that contains a firing order for borders?
>Petry: I haven't used the word firing order. No policeman wants to shoot at a refugee. I don't want that either. But using arms is the last resort. It's crucial that we don't let it get so far, and slow the stream of refugees by making an agreement with Austria and monitoring the EU borders.
That much for the actual interview. As for the interpretation of the actual law, the police said that no policeman would shoot at a refugee, as it wouldn't be proportionate to shoot an unarmed person (proportionality is an important concept for these kind of things in Germany).
[Later she apparantly got asked whether she also "wants to shoot children and women", she just quickly answered "yes". This is against the law, as the law does explicitly forbid shooting at children.]
Not sure if that helped, tell me. :)