Thanks for raising the issue, and thanks to Mike-And-Jane0 for giving charging costs; this puts it into context.
I had to visit our chalet whilst the guests were in residence. I was there to deal with a potential wasp situation and was surprised that the car had a cable connecting it to the house. No mention was made before this.
It is difficult to raise the issue with the client for the following reasons; 1. my French is not sufficiently fluent to change from wasps to "how much is this costing me and is my electric circuit capable of handling the current for your car"; 2. the whole family is there - I need to speak to the driver alone.
The car looks like it could eat a good mealsworth of electricity, but how many other gadgets are charged at the proprietor's expense. When I go on holiday I have one mobile phone, and it takes/gives calls and texts so doesn't need charged for about 5 days.
I shall be reviewing the listing in order that future clients forewarns us.
best wishes
Derek