Celebrate noisily - King of France has rest disturbed (7)
I believe the answer is:
roister
'celebrate noisily' is the definition.
(roistering is a kind of celebrating noisily)
'king of france has rest disturbed' is the wordplay.
'king of france' becomes 'roi' (I've seen this in another clue).
'has' says to put letters next to each other.
'disturbed' indicates an anagram (the order of letters is disturbed).
'rest' anagrammed gives 'ster'.
'roi'+'ster'='ROISTER'
(Other definitions for roister that I've seen before include "Have noisy fun" , "Carouse" , "Behave boisterously" , "Celebrate noisily" , "I rest or (anag) - engage in noisy merrymaking" .)