Walk in Montmartre a delight (5)
I believe the answer is:
tread
'walk' is the definition.
(I know that tread is a more specific form of the action the walk)
'in montmartre a delight' is the wordplay.
'in' indicates the answer is hidden within the clue.
'TREAD' can be found hidden inside 'montmartre a delight'.
(Other definitions for tread that I've seen before include "Press (grapes by foot)" , "Trample" , "A measurement of tyre" , "Part of flight" , "Moulded part of a tyre" .)