Le Voyage en douce (aka Sentimental Journey)
Of course, I haven’t seen this, but I copy some information here.
Le Voyage en douce (1980)
Plot summary from IMDB
Lucia and Elena are best friends since childhood. They take a car trip from Paris to the country. Their conversations are overtly intimate, but more revealing is their tacit understanding of each others’ personality and desires.
(click to enlarge)