This is a Federal Signal AS 320 Siren used by the Hungarian Police, as far as I know.
I haven't found a single mod for it, so I've decided to make one myself.

I have ripped the sounds from the following video: https://www.youtube.com/watch?v=I_puQpVNJbg
All credits go to the original uploader!

Installation:
Copy all the files to \Rockstar Games\Grand Theft Auto V\plugins\SirenMastery\
Requires SirenMastery to work!
Feel free to adjust the volumes in the .xml file provided if the levels are too low for you.

I've used the following car for the sake of the screenshot:
https://hu.gta5-hub.com/paintjobs/hungaryan-police-bmw-525
Hungarian Police BMW 525 by jezus9