They are small campsites Mike and only licensed for up to 5 units at a time, Certified Locations (CL) is what the Caravan Club call them and Certified Sites (CS) is the Camping & C'van Club nomenclature for the same thing. EHU does stand for elec hook up and is common parlance all over the camping fraternity - whatever you happen to camp in!
An Aire - Aire de Stationnement de Camping Cars - Stellplatz in Germany, other names in other European countries is what it says - like a carpark but specifically for actually camping on (which is banned in 'normal' car parks - you can neither sleep nor cook on them but shush, we have been known to make a cuppa on a carpark notwithstanding that! Mind you - we've been known to do that when in cars when we're on the way to somewhere with tent and all the junk on board) but without fancy facilities - sometimes they are free or a very small charge, like €6 a night instead of eg €36 on a proper campsite. Idea is to bring passing trade to the local area, be that Disneyland Paris/the Puy du Fou or a town like Niort or Narbonne. Also at beauty spots - beaches and lakes, or ski resorts etc. where you just don't want to pay several arms and legs for a sanitary block, swimming pool and kids playground, onsite restaurant etc. that you have no intention of using or desire to look at! A lot have fresh water and wc cassette emptying/waste water disposal on site (as all CS and CLs have to in the UK) and some don't.
It is a totally different mindset again to tent or caravan camping! (or indeed having a Moho, but only ever staying on 'proper' campsites) In the UK, many pubs are now providing facilities for overnighting Moho visitors, very often free for one night if you eat in the pub.
