Peter,
Click on VAC Aerodromes and then type the ICAO code on the small window on the lower left. That will give you the VAC, which, in France, contains all the required details of the VFR only airfields, including telephone numbers.
Generally, fields that don’t have an ATS neither have a person responsible for refuelling and invoicing. So it’s either self serve via an (own) fuel carnet or by some some help from “someone”.
I was looking in the eAIP. Bizzare why it is not in there.
I have just heard that LFMW is cash, as well as the TOTAL card.
I am using the SIA site a slinked above. Actually I am using the fantastic ipad app “iVAC” (which does nothing else than link to that site.
The eAIP does show only Ad sections for IFR airports, since for the VFR fields, the details are on the last page of the VAC.
Anyway, re LFMW and LFMZ it is quite simple. Lézignan has (within punblished hours!) an AFIS (and thus someone who can sort out the refuelling for you. Still cash only. But the AFIS is French-only (an exception rather than the rule) so you are not OK unless you can do the two-way radio in French.
Castelnaudary has no ATS all (but no french-only requirement either). One can thus legally fly in using English, but it’s a bit more dangerous, because there may be pilots around who don’t understand any of your calls well. So make sure at least that you get the pronounciation of the airfield name right, so as to at least make them aware someone else is around. On the fuel side, if you don’t the required fuel carnet, you will have to prearrange someone to be there and sell the fuel, as, having no AFIS, there is no “official” attendance there.
I guess everybody will go to LFMK anyway and then it will be interesting if the airport will tolerate parking aircraft “off the yellow lines” or not. 
It would then make sense for intra-schengen French speakers to fly to Lézignan.
Shall we move the fly-in to some country where stuff is simple, the airports want aircraft to land there, and it is still really scenic and has great food e.g. Croatia? 
What are the suggested “proper airports” which can be used as IFR alternates, taking transport into account?
For example I won’t be able to divert to LFMW and LFMZ, other than on a mayday.
Is Castres LFCK any good? It has some military activity. Toulouse LFBO looks like being accessible by train.
Current total:
Interesting how perceptions vary. For me, on balance, France is no. 1 for flying in Europe.
Apart from the nice scenery on the coasts, I find Croatia rather mediocre due to (mainly) the low number of airports and (secondarily) the big airport fees at some places, as well as the huge amount of controlled airspace.
Just enjoy the trip and see what comes.
I have 5 coming at this point with a possible 6th as one may drop out and two take their place. Complicated. I will be at MGTOW. So I need a looong runway. 3000’ does not cut it. So I have to go into LFMK.
I am simply trying to organise this fly-in as far as one can (given that I cannot speak any French) so it works for everyone, and while I agree that “it should be all right on the night” tends to work, especially in France, I find it a bit worrying because this is also a country where if you upset some official, you can get big trouble.
IMHO LFMK cannot park 28 planes on the area where GA visitors are permitted unless they push some on the grass (or the grass is OK to taxi on and the tarmac/grass transition is OK to taxi across).
The one thing we seem to have established that LFMK will not give you fuel unless you have the AIR BP card, whereas LFMW has a cash option.
The airport won’t let me park anywhere else on the apron either which is not exactly going to help with fitting everyone in.
Five tailwheel aircraft might be allowed on the grass. My French is not up to much, but could give them a call.
I think you guys are worrying too much. It’s a wonderful problem to have so many people interested!
But in reality, two things will happen:
1. 50% of the people listed, won’t turn up for various reasons. Weather at Carcassonne, weather along their route, a change in personal plans, aircraft gone tech, passengers backing out, wife/kids commitments, or they simply were out late the night before and don’t feel up to it on the day. Or maybe they were just 50/50 about coming in the first place anyway.
2. The airport will shrug their shoulders when more aircraft turn up and if the aircraft sort themselves out, they won’t get involved. If “we” solve the problem for they, they’ll just look the other way. They might say that they can’t accept 20 aircraft, but when one too may turns up they then to find a way. And if it doesn’t work, they that aircraft can drop the passengers and bags and fly to one of the other local airports.
Having so many is good motivation for people to turn up early. If people are coming with friends in another aircraft, perhaps they can drop their passengers off at Carcassonne, and then leave one aircraft to another airfield? A sort of shuttle service among friends
Fuel isn’t so much of a problem. Most people can stop somewhere enroute if necessary. That’s what had to happen for Corsica anyway, and it didn’t stop it turning out to be a wonderful flyin
