French underground (5)
I believe the answer is:
metro
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">french underground</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for metro that I've seen before include "French underground" , "what moves many Parisians" , "Parisian underground system" , "Parisian underground railway" , "Urban railway system" .)