Bar knowledge about American in German city (10)

'german city' is the definition.
The definition suggests a singular noun which matches the answer.

'bar knowledge about american' is the wordplay.
I cannot quite see how this works, but
'bar' could be 'lever' (lever is a kind of bar) and 'lever' is found in the answer.
'american' could be 'us' (abbreviation for United States) and 'us' is located in the answer.
'knowledge' could be 'ken' (ken is a kind of knowledge) and 'ken' is present in the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

'in' is the link.

Can you help me to learn more?