Sweden's PM once recalled the French head of state without rest (9)

'without rest' is the definition.
('rest' can be 'sleep' (sleeping is a kind of resting) so maybe 'without rest' can be ''sleepless')

'sweden's pm once recalled the french head of state' is the wordplay.
'sweden' becomes 's'.
'pm' becomes 'peel' (19th-century prime minister Robert Peel).
'once recalled' says the letters should be written in reverse.
'the french' becomes 'les' (plural form of 'the' in French).
'head of' indicates taking the first letters.
The initial letter of 'state' is 's'.
'peel' in reverse letter order is 'leep'.
's'+'leep'+'les'+'s'='SLEEPLESS'