Lights out here in France, it's decreed (8)
I believe the answer is:
official
'decreed' is the definition.
Both the answer and definition are adjectives. Maybe you can see a link between them that I don't see?
'lights out here in france' is the wordplay.
'lights' becomes 'offal' (I've seen this before).
'out' means one lot of letters goes inside another.
'here in france' becomes 'ici' ('here' in French).
'offal' going around 'ici' is 'OFFICIAL'.
'it's' is the link.
Can you help me to learn more?
(Other definitions for official that I've seen before include "It's no rumour - he's in charge" , "Person appointed by authority" , "Relating to authority" , "Employee of bureaucracy - it's authorized" , "Formally approved" .)