Leave behind organised tour -- it's heading for Paris (8)
I believe the answer is:
outstrip
'leave behind' is the definition.
(outstripping is a kind of leaving behind)
'organised tour it's heading for paris' is the wordplay.
'organised' indicates anagramming the letters.
'heading for' says to take the initial letters.
The initial letter of 'paris' is 'p'.
'tour'+'its'='tourits'
'tourits' with letters rearranged gives 'outstri'.
'outstri'+'p'='OUTSTRIP'
(Other definitions for outstrip that I've seen before include "Exceed; move faster than" , "Surpass, overtake" , "Exceed, overtake" , "Move faster than (someone else)" , "Go faster or do better than" .)