At Cannes, "I, Robot" cut short a monsieur's bottle of wine (8)
I believe the answer is:
jeroboam
'bottle of wine' is the definition.
'jeroboam' can be an answer for 'bottle' (jeroboam is a kind of bottle). I am unsure of the 'of wine' bit.
'at cannes i robot cut short a monsieur's' is the wordplay.
'at' is a charade indicator (letters next to each other).
'cannes i' becomes 'je' (I can't justify this - if you can you should believe this answer much more).
'cut short' means to remove the last letter.
'monsieur' becomes 'm' (French abbreviation - like Mr for Mister).
'robot' with its last letter removed is 'robo'.
'je'+'robo' is 'jerobo'.
'jerobo'+'a'+'m'='JEROBOAM'
Can you help me to learn more?
(Other definitions for jeroboam that I've seen before include "Four bottles of wine in one" , "a lot of bottle?" , "Wine bottle 4-12 times the ordinary size" , "Large bottle of champagne; a Rome job (anag.)" , "'Large wine bottle, equal to four standard ones (8)'" .)