I know you've travelled a lot Scotty, but all the same I suggest you advise them of two very important things:-
(priority from the right): If a road to your right has no STOP or GIVE WAY markings at the junction with your road (it's the same as ours - either a solid or broken white line), the vehicle approaching from the right has priority ... and therefore will
drive straight across your bow if they are turning left, or pull out in front of you at low speed if they are turning right. This can happen in villages/towns/cities at low speed, or much faster on country roads.
Because of so many accidents in the past, especially involving tourists, nowadays the French authorities have almost entirely ditched Priorite-a-droite
in the countryside on main roads (Nationals), but it still applies a lot on B roads and in built up areas. Brits are caught out by this all the time, often leading to road rage as the French know they are right so will make a mountain out of a molehill to make their point. Understandable I suppose, but 9 times out of 10 it leaves British drivers wondering why? Now you know!
BTW, I realise you'll only be in France for five seconds, but even in Calais there's one particular junction which constantly catches out the unwary. It's practically opposite the railway station, but the precise location isn't the point. The accidents at this black spot are always low speed collisions, more of a tap or a coming-together really, but it does emphasise what I'm on bleating on about. Every
junction in town can spoil your day, so beware.
2. As an example - after having lunch, so often British drivers will drive out of a car park and turn left or right on the wrong side of the road!
It happens all the time, it's happened to me and several people I know. It's human nature. We're so used to our way of driving, we simply forget. Once out of the car park however (assuming you are on the correct side of course!!!) you can drive all day long with no problems at all, it is simply that first turn which can catch you out.
Interestingly, just the other day it happened the other way around to my German friend Ralf while driving in Coventry - he drove on the wrong side here! Exactly the same thing occurred. Although he has been driving in this country for the past couple of years, so should be used to driving on the left, he pulled out of a company car park on a trading estate, turned left and promptly drove straight across to the other side of the road, so suddenly we were facing oncoming traffic! Actually it was fine as the "oncoming traffic" was a car some distance away, but if it had been a truck even travelling at low speed, it would have been a 'brown trouser' moment!
So beware, 99% of the time Continental driving is fine, but you can never really drop your concentration like you can here - they do after all drive on the 'wrong side of the road'.