Luke in France I had clearly understood (5)

I believe the answer is:

lucid

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'clearly understood' is the definition.
(I've seen this in another clue)

'luke in france i had' is the wordplay.
'luke in france' becomes 'luc' (I can't explain this - if you can you should give a lot more credence to this answer).
'i had' becomes 'I'd' (contraction).
'luc'+'id'='LUCID'

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(Other definitions for lucid that I've seen before include "Transparently clear" , "Clear-cut" , "Clearly presented and easily understood" , "Clear, intelligible" , "Limpid" .)

I've seen this clue in The Sun.

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