Shudder inside Montmartre morgue (6)
I believe the answer is:
tremor
'shudder' is the definition.
('tremor' can be a synonym of 'shudder')
'inside montmartre morgue' is the wordplay.
'inside' indicates the answer is hidden within the clue.
'TREMOR' can be found hidden inside 'montmartre morgue'.
(Other definitions for tremor that I've seen before include "Small earthquake" , "Vibration from earthquake" , "A slight shake, perhaps of earth" , "Minor earthquake" , "Vibration - shaking" .)