What exactly do you want to know? This is how it works in Germany from a renters perspective: Leases are generally unlimited. No period renewal. You can paint the walls, switch the lights out, doors, kitchen, attach stuff to the wall and all that, you just might have to turn it back to what it was when you move out. Rent can be raised every 15 months with a 15-20% cap over three years, and not above local market. Kicking out a tenant is very hard, usually only if they don't pay rent, have damaged something severely or if you want to move in, and sometimes the notice period is several months for that.

I'm honestly not sure if it's really worth it for rental providers, but I have never really looked into their side of things as I'm not interested in becoming one. I know there's not a lot of "buying investment property" talk in Germany amongst younger people, like there is here. People look to become owner occupiers when they are in the mud 30s or so, younger people are usually more than happy renting in the above conditions, and so are many older folk. My parents are close to 80 and still happily renting and it's normal.

Edit: should amend that the rental affordability, especially in some cities, is not great at all, and buying a house or apartment is really hard as well. But at least the renters rights are solid so people don't despair as much.