Dodgy Megane windows are a well known problem. My son-in-law cured his by removing th edoor card, taking off the control module on top of the window motor, disassembling that, cleaning out the moisture and carefully dryoing the module, - i don't recall whether he sued WD40 - and reassembling with a dab or two of silicone rubber to seal.
There are aftermarket replacement modules available as well, for about £20
A google search is all you need.
acp, April 2017
