Hi Tony,
First of all have a great time in France.
I commute to Rotterdam - via Calais - on a regular basis, and there's a bit more to driving in France than just the physical act.
Away from Calais, you'll notice that driving on the motorway network is easy - traffic density is low - and by the time you get to Paris you should be experienced
You'll need your car insurance certificate and V5 or proof of ownership if this is a lease or company car, and the driving licenses of those who drive the car.
You'll need to adjust the car headlamps for European driving - either flip the UK to symmetric lever (if fitted) on the headlamps, or fit beam benders, or lower them all the way down (if you have headlamp control - least satisfactory)
GB stickers or the Euro numberplate (blue strip with GB on left hand edge) on both car and caravan.
A complete set of spare bulbs (Halfords) for the car is a good idea - if a bulb blows you should be able to fix it straight away - and this will save you a fine if pulled by the police for a faulty light
When driving into small towns, you may notice a yellow diamond (about 2ft on each edge) at the town outskirts - this means Priority from the right is now enforce - so expect drivers to pull out from side streets with warning - although most drivers check anyway. When you leave the town you'll notice the same yellow diamond crossed out - return to main road priority (like the UK).
The town sign often acts as the start of the town (50 kph) speed limit.
You'll be familiar with the other roads signs - these are standard throughout Europe
If you overtake on a motorway, you must return to the inside lane as soon as practical - lane hogging will be punished by the police.
At the same time you'll notice French drivers in the overtaking lane with their left indicator flashing - often in a stream of cars overtaking slower traffic - they are indicating that they intend to keep in that lane to overtake other slow traffic ahead - it's not a "get out of my way" - so don't get uptight if someone appears behind you with thier indicator flashing
Robert