In retrospect, the French inherited units in an old French colony (7)
I believe the answer is:
senegal
'an old french colony' is the definition.
The answer and definition can be both locations as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'in retrospect the french inherited units' is the wordplay.
'in retrospect' shows that the letters should be reversed in order (in retrospect means looking back).
'the french' becomes 'la' (one of the French words for 'the').
'inherited units' becomes 'genes' (I have seen 'Units of DNA ' mean 'genes' so perhaps 'units' could also mean 'genes'. I am not sure about the 'inherited' bit.).
'la'+'genes'='lagenes'
'lagenes' reversed gives 'SENEGAL'.
'in' is the link.
Can you help me to learn more?
(Other definitions for senegal that I've seen before include "Dakar is its capital" , "Land" , "Northwest African country" , "Republic in northwestern Africa" , "French-speaking west African republic" .)