Informal French restaurant (6)
I believe the answer is:
bistro
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">informal french restaurant</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 bistro that I've seen before include "Little restaurant" , "Small informal french-style resturaunt" , "family concern perhaps" , "Cheap restaurant" , "'Small, inexpensive restaurant (6)'" .)