'Kam čert nemůže' (Czech film from 1959). Jana Hlavácová in a pale yellow/natural-coloured semi-transparent plastic mac. There are 9 parts to the uploaded film on You Tube - the mac scene coming in the last part. The English title of the movie is 'When The Woman Butts In'. Enjoy!
The mac scene is from 5'-25" to 7'-32".
URL: https://www.youtube.com/watch?v=ysY59MQXolg