French tower designer (6)
I believe the answer is:
eiffel
'french tower designer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eiffel that I've seen before include "Creator of a Paris landmark, built in 1889" , "& 20 Across Paris landmark" , "Famous tower designer" , "French tower-designer" , "Famous tourist tower in Paris" .)