THE DIFFERENT CHANCES FOR DIFFERENT ITEMS

Single flats or apartments

Besides rental homes and offices buildings single flats and apartments are a future market.
A wide range of assisted living ("Betreutes Wohnen") within cities will be a further special market.

Frankfurt, Hamburg and Munich are most interesting for flats and apartments.
Generally, you should buy preferably in well reputated areas.
But: in many cities there are areas which very likely will become in a few years very sought for.
There are often certain indicators, which will show the beginning of such development.
Often areas, which attract students and artist become in a few year very searched for.

Single flats or apartments can be bought as one room studios or as multi-room flats.
They can be rented both furnished or unfurnished.
Whether furnished flats can be rented easily depends on the common practice of the local market. Are there students?
The return on investment may be between 4% and 6%, rarely higher.
In good, well reputated areas NOT rented flats are most searched for and the price is often remarkable higher, than for a rented flat.

The rental law regulates rents (for flats) in Germany strongly.
One legal possibility to rise the rent are alterations and implementations, which improve the flat essentially. But such a conversion normally must be agreed upon with the tenant.
A difficult issue!

Your calculation should be based on the official list of average rents.(Mietpreisspiegel) On top of this list you might add (under certain circumstances) some extras - but you should not expect, you could put up rents within a very short time.
You normally can do so only within small steps and within certain absolute limits.
There are only a very few exceptions.

The laws differ between normal flats and furnished flats.
An apartment unfurnished is rented (generally) with an unlimited lease contract.
The contract is automatically prolonged and runs until notice is given by either party.
The regular notice period for the tenant is three months. The period for the owner is three months within the first years, 6 months after 5 years and 9 months after 8 years.
Beside this normally a contract can be canceled by the landlord only under specific circumstances.
If you want to use the flat (or house) one day for yourself you should make a specific (written) comment, when the contract is signed; Even with such a comment, it might be difficult, to abandon the lease . The specific legal aspects should be elaborated by an experienced lawyer.
Furnished rentals can have shorter cancellation periods. Whether it is sensible, to rent a furnished flat, has to be discussed carefully case by case. An locally experienced agent should be involved.
A general advice is not possible.
"Furnished" must be furnished. It must be more, than just a kitchen and a bed.

If you buy a single flat, you will become member of a "Wohnungseigentümergemeinschaft"/" WEG" (the group of owners within a housing estate).

The rights and duties of the owners amongst each others are defined by "Wohnungseigentumsgesetz" (WoEigG) There might by exceptions from these general rules, if stipulated so in the "Teilungserklärung" (declaration of partition).
The main structure of the building belongs to all owners and has to be kept in good condition by all owners. Because of that, you should have inspected not only the single flat, you want to buy, but also the whole housing estate. Before buying it is sensible to read the yearly reviews of the property management. This review has to be agreed upon by the owners.
These reports can give to you a good impression about the former and the likely further problems, which might be linked with the property.