I am sitting here somewhat pissed off I will explain why under a thread about workshop expertise or lack of), so I thought I would bring something up to date. I have found several forums (or fora), about the safety of sleeping at 'aires' in France. Many reports are outdated and dozens suggest it is dangerous.
As with a layby which is a lay-by, there are different kinds of aire. Aire (area) with services or aire without. You can sleep in both.
France has put great effort into the road and motorway system with the emphasis being on safety. They don't want you falling asleep at the wheel - something I am prone to do. So they have upgraded their motorway service aires offering decent restaurants, nomad office space, playgrounds, picnic areas, toilets, showers and even washing machines and dryers! They wash, polish and fill you up and your vehicle.
You can PARK and sleep for a limited period overnight - 72 hours. I have for many years parked and slept in cars, alone and now in my van on long journeys. I choose a visible location, near other motorhomes and within easy reach of the all night services. Nowadays there are plenty of people stopping over. I prefer the service aires to stop in because there are more people.
France welcomes her van and motorhome travellers and the investment in the roads and services shows this. There always is a risk, but I am comfortable stopping over as a solo vintage female. November 2024.