What's with the unusual siren sounds throughout Blochin?

The first season of Blochin: Die Lebenden und die Toten naturally featured many sirens of police cars to be heard throughout the story. However, what was very confusing to me about those sirens was that they were distinctly different from a usual German police siren and sounded much more similar to the siren of a US police car.

Now I'm admittedly not at the pulse of time in modern police developments in Berlin, but it seemed unusual that this would be the siren of a German police car, especially since the exact sound of police sirens seems to be legally regulated. But still, was this in any way realistic as to police cars used in Berlin at the time of production or was this indeed a deviation from reality there?

In the latter case, why was this change done? Was this for legal reasons of not being able to use the standard siren (though, I've heard millions of normal police sirens in TV productions and movies already)? Or was this done for artistic reasons? I know that the producers very much strived to immitate the style and success of current US TV dramas (specifically naming Breaking Bad as a big ideal). So could this just have been an homage to US TV-shows to use a US police siren? Was there any word from the producers/directors on this? All in all it was quite a bit irritating even if done purely for style, so I hope there is some more elaborate reason behind this.