Of all the Paris airfields, the one with the easiest and quickest public transport links is St Cyr L'Ecole, but it's certainly about as challenging as it gets in terms of surrounding airspace and local procedures. Requires a full briefing from someone in the know and a good session with Google Earth to prepare. Hence why see almost no foreign aircraft there, although their circuit often gets busted (scarily so...) by non-F-reg regularly in Summer.
Toussus nearby is a good choice too logistically, with taxi or bus to nearest RER. However,local procedures are again strict (picture plods with binos checking out your circuits, I kid you not...), although probably not an issue with G-reg inbound on wider joins.
Agree all that's been said on Pontoise, Lognes and Meaux. If was coming in from over the Channel, especially for first time, I'd make my life easy and head to one of the fields to the E/NE and keep away from trouble might get into trying to head round to SW.
If needing to head to SW corner of Paris, I'd try and get in touch with someone at one of the clubs/ATC at the airfields and get all the relevent diagrams.
Last edited by betterfromabove; 7th Aug 2012 at 23:04.