Clue: Wrongly understand disadvantages in fog on French road (11)
Answer: MISCONSTRUE
Explanation: Definition: Wrongly understand
 CONS(disadvantages/that which serve as arguments against, say, doing something) **contained in**(in) MIST(a fog/a cloud of tiny droplets or particles suspended in air) **placed above**(on, in a down clue) RUE(French for "road").