Although the question phrase "was für...?" (= what kind of...?) is comprised of a pronoun and a preposition, it should be considered as a single concept which behaves according to the rules outlined above. This means that the case of the noun that follows "was für...?" depends on the role of the phrase in the clause and not on "für" - i.e. it does not mean that any noun following "was für...?" is automatically in the accusative case. Equally, "was für...?" can be preceded by a preposition which then determines the case of any subsequent noun.
Look at the following examples using the weak masculine noun "der Mensch" (see previous page):
The German flag Grammar 14: Questions involving "was für...?"
Nominative
Was für ein Mensch ist er?
("What kind of a person is he?")
Accusative
Was für einen Menschen siehst du?
("What sort of a person can you see?")
Was für Freizeitmöglichkeiten gibt es im Hotel?
("What sort of leisure facilities are there in the hotel?")
Dative
Mit was für einem Menschen ist deine Schwester verlobt?
("With what sort of man is your sister engaged?")
In was für einer Pension übernachten wir?
("What sort of guest-house are we spending the night in?")