Originally Posted by
MSPeconomist
Finally, when you say the end of summer be VERY careful about your travel dates. Most of France migrates to the south for the month of August (traditional vacation time which also coincides with school break) and the expressways becomes big parking lots around August 31st. It's common to see stories in the news of families being trapped on the road and unable to move for ten hours or more. Especially if you need to go to the airport around such dates, do not underestimate the time that might be reequired. You should do as the Europeans do and pay attention to school vacation periods in other countries as there can also be massive movements of German etc. tourists on certain dates.
Goodness me, yes, it gets very busy. I've been caught in hours-long traffic jams (with a half hour bonus at the tollbooth if you try to get out and take the country roads). A good guide is here:
https://www.bison-fute.gouv.fr/previsions,10741.html
Pop in the dates and it'll tell you when to brace yourself.
Do plan parking in advance. If you happen to go to Monaco, this is a must! France does like its underground parking too, be aware. Corners and spaces will be tighter than you'll see in the US (and typically fully perpendicular, not angled). So, choose your size of car carefully! This is a great resource:
https://www.parkopedia.com/
And, as mentioned, do learn the pictographic road signs.