Some soberness in the Swiss capital (5)
I believe the answer is:
berne
'swiss capital' is the definition.
(capital of Switzerland)
'some soberness in' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'BERNE' can be found hidden inside 'soberness in'.
'the' acts as a link.
(Other definitions for berne that I've seen before include "Swiss capital" , "Capital of Switzerland" , "Swiss city (1886 copyright convention)" .)