Feel bad if taken in by French engineer (6)
I believe the answer is:
eiffel
'french engineer' is the definition.
(Gustave Eiffel)
'feel bad if taken in' is the wordplay.
'bad' is an anagram indicator.
'taken in' means one lot of letters goes inside another.
'feel' anagrammed gives 'efel'.
'efel' going around 'if' is 'EIFFEL'.
'by' is the link.
(Other definitions for eiffel that I've seen before include "Famous tower designer" , "& 21 Across Parisian landmark" , "Parisian tower builder" , "& 20 Across Paris landmark" , "French tower-designer" .)