Paris in tatters: end of mortal coil (6)
I believe the answer is:
spiral
'coil' is the definition.
('spiral' can be a synonym of 'coil')
'paris in tatters end of mortal' is the wordplay.
'in tatters' indicates an anagram (I've seen this in other clues).
'end of' suggests the final letters.
The last letter of 'mortal' is 'l'.
'paris' anagrammed gives 'spira'.
'spira'+'l'='SPIRAL'
(Other definitions for spiral that I've seen before include "Sir, pal winds in continuous loops" , "Sort of staircase (could be vicious?)" , "design for some staircase" , "Shape of a corkscrew or spring" , "Mushroom" .)