Where do you get all that from? Except for famous cases like the Rote Flora in Hamburg or i guess Berlin in general there's not a lot of squatting going on in Germany, or is there?

In Germany squatting laws dictate you have to openly live at a place for 30 years and the property needs to be registered to your name in order for you to be able to claim ownership.So here it can hardly be a measure anyone can take to get a cheap place to live.

I have several friends who have squatted abandoned buildings in Europe. I have other friends who live in otherwise abandoned buildings under agreement with the owner to prevent squatters breaking in to the building. When I moved into my house several years back it looked abandoned (because it had been before buying it), and when I invited friends over for the first time some assumed I was squatting there upon arrival. Squatting is really not an unusual thing. Squatters aren't squatting in order to claim ownership. Often they're students looking for a cheap place to stay.

No, there is not a lot of squatting going on in Germany. AFAIK, the only EU countries with rather active squatting scenes are Italy and Spain, but my information is probably 20 years out of date.

Same as in Spain. I know multiple cases of "okupas", not of what OP describes.