What kind of electrical sockets are used in French campsites?
If you go along to a good caravan/camping accessories shop and ask for advice there they will sell you an adaptor which you plug into the french campsite mains supply. This adaptor has about 30cms of cable attached to an “English-style” mains socket into which you can plug your normal 20metre mains cable. One little word of warning: french campsite electicity supply is sometimes wired up to reverse polarity so you should also buy a polarity tester while you’re at it. You can also buy a polarity reversing adaptor to use if (and it’s a small if) you do have the misfortune to come across this. I have camped and caravanned in France since the 1960’s and have only come across this about 5 times.