Information about armed French policeman (8)
I believe the answer is:
gendarme
'french policeman' is the definition.
(French military police officer)
'information about armed' is the wordplay.
'information' becomes 'gen' (gen can informally mean information).
'about' is an anagram indicator.
'armed' anagrammed gives 'darme'.
'gen'+'darme'='GENDARME'
(Other definitions for gendarme that I've seen before include "An arresting Frenchman?" , "Member of the French police" , "French officer - merge DNA (anag)" , "Foreign policeman" , "French copper" .)