Sprung by the French? Fitting! (5)
I believe the answer is:
leapt
'sprung' is the definition.
(I've seen this in another clue)
'by the french? fitting' is the wordplay.
'by' is a charade indicator (letters next to each other).
'the french?' becomes 'le' ('the' in French).
'fitting' becomes 'apt' (I've seen this in other clues).
'le' put next to 'apt' is 'LEAPT'.
(Other definitions for leapt that I've seen before include "rose fast" , "gone up dramatically" , "Jumped, sprang" , "Took off" , "Jumped on plate" .)