"The City of Light" (5)
I believe the answer is:
paris
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the city of light</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for paris that I've seen before include "investment resulted from his action" , "French department" , "City; Juliet's betrothed Count" , "Prince who abducted Helen, starting a long war (see 8)" , "Arc de Triomphe city" .)