Former West German capital (4)
I believe the answer is:
bonn
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">former west german capital</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for bonn that I've seen before include "West German capital, 1949-90" , "Rhine city" , "W German capital 1949-90" , "Capital of the former West Germany" , "Capital of West Germany, 1949-1990" .)