Deliberately divert from French bar (6)
I believe the answer is:
derail
'deliberately divert' is the definition.
I can't tell whether this defines the answer.
'from french bar' is the wordplay.
'from french' becomes 'de' ('from' in French).
'bar' becomes 'rail' (rail is a kind of bar).
'de'+'rail'='DERAIL'
Can you help me to learn more?
(Other definitions for derail that I've seen before include "Cause to leave the tracks" , "Cause to come off the tracks" , "Force off track, like a train" , "get off the line" , "go off line" .)