Is below standard for a European capital (5)
I believe the answer is:
paris
'a european capital' is the definition.
(I've seen this before)
'is below standard' is the wordplay.
'below' says to put letters next to each other.
'standard' becomes 'par' (I've seen this before).
'is' after 'par' is 'PARIS'.
'for' acts as a link.
(Other definitions for paris that I've seen before include "where he got plastered?" , "Helen's abductor" , "Arc de Triomphe city" , "Capital of France" , "'I Love - - ', song by 14" .)