Decide before you go whether you'll have absolute faith in your sat-nav (assuming you're taking / using a sat-nav), or whether you'll use conventional maps and/or printouts. If you rely on sat-nav then there'll inevitably be a junction where you wonder "Why the hell is it taking me that way ?" and, being in a foreign land, you'll have no idea if it's wrong or right. Michelin do an excellent online route planner that you can print out - it even gives pictures of what the junction signs look like so you can match them up as you take them - that sort of thing can be very reassuring.
https://www.viamichelin.co.uk/
Toll roads are quite painless, although I've known there to be horrendous queues at times due to the fact they seemed to want to put 32,000 cars through one and a half toll booths

Cash and cards are accepted - this gives details of what cards can be used, but take a back-up one if you have one as I've known them be fussy.
http://www.autoroutes.fr/en/payment-methods.htm Toll booths are automated and mostly also manned on the main routes.
Toll pricing can be checked via here :
http://www.autoroutes.fr/index.htm?lang=en If you think our road fund licence is expensive - try driving down to the South of France and back on toll roads !! Yep - they're fast and good, but they're also expensive over long distances.
What insurance cover you've got depends on your insurer, but I think all insurers cover you to a bare minimum for short trips. You may need to let them know before you go, but - again - it depends on your cover. For peace of mind, I'd HIGHLY recommend you make sure you've got full comprehensive cover and you let your insurers know before you go. In the unfortunate event that you have an accident whilst over there, make sure you take down ALL relevant details that the insurers want. Having been hit whilst in France by a geriatric German, I know that it's reassuring to know you can sit back and let the insurers fight it out as you've done everything right ! There is such a thing as a 'European Accident Statement' form that should be filled in in the event of an accident. It's to provide you and the other driver with an agreed statement. Whilst your insurers may not be bothered about it, the other person's might. Undoubtedly there will be people who will say : "I've never seen that before / I never bother with that / Nah, you don't need that" etc, etc. That's all fine and dandy.... right up until the point you actually need it.......
Make sure you've got
GOOD breakdown cover. You can buy this for short trips from the usual online sources.
An overview of French driving laws and regulations (as at 20/02/2017) can be found here
https://www.theaa.com/european-breakdow ... -in-france with an option on the page to download a more comprehensive guide.