Part of film featuring the French soldiers (7)
I believe the answer is:
element
'part' is the definition.
(I know that element is a type of part)
'film featuring the french soldiers' is the wordplay.
'film' becomes 'ET' (E.T. the Extra-Terrestrial).
'featuring' means one lot of letters goes inside another.
'the french' becomes 'le' ('the' in French).
'soldiers' becomes 'men' (men can mean a group of soldiers).
'le'+'men'='lemen'
'et' placed around 'lemen' is 'ELEMENT'.
'of' acts as a link.
(Other definitions for element that I've seen before include "Eg, one dn" , "An abstract part of something" , "Trace" , "Comfort zone" , "of the weather" .)