score:4
You should be looking for accommodation that is explicitly listed for short stays.
The majority of "regular" German flats-for-rent come unfurnished and you will have a hard time convincing the landlord to rent it to you when there are other people interested in lending it for >=12 months. That is especially true if you do not have a residence permit. Also, rules such as that the walls need to be freshly painted when moving out are by no means uncommon.
Consider looking for places that are listed as vacation rentals. Your favorite search engine should find you some sites to search for them. AirBnB may also be an option (despite the fact that the legal situation for people offering accommodation within Germany on AirBnB is a bit tricky).
Upvote:3
Couldn't be easier, just click here
http://www.holiday-rentals.co.uk
or here
There are literally 10s of thousands waiting for you
Holiday rentals (you rent one week at a time) are huge in Europe ("gites", yo'd say in France for example)
I wouldn't bother with airBnB - that's just a trendy start-up, focussed on one-night-at-a-time things
There are 10s of thousands of well established holiday-rental properties on holiday-rentals.co.uk -- you'll have a vast range of choices.
Note that I say ".co.uk" just since it's in English - they have sites in every language. it's a huge company.
You mention it's only you, so I clicked "sleeps 2" and immediately found 4000 options..again you don't mention what part of germany (it's a big place!)
You can easily pay as little as 20 or 30 euros a night...(noticed I selected "low to high price")