Travel between Switzerland (and Norway?) and other Schengen countries, especially France

All this seems very complicated.
When I was based in EBLG (EU-SHENGEN-EURO zones), 2 years ago, I could easily fly to UK, Switzerland and about anywhere in my reach.
I made a 2 hour flight to Lausanne (to say hello to @Flyingfish;-) in 2012. Now, I would either need to land in EBLG (10 minutes from EBST my home base) and pay around 150€ for landing, handling, etc., or make a stop in LFGJ or LFSP (with PN) before landing in LSGL. You can add at least 1 hour to the flight.
I have been flying to several french airports last year. I never minded about which one was Customs enabled or not. And never was bothered. I guess I can still freely fly in UE-SHENGEN zones whiteout PPR,PN. My last flight out of Belgium flight was to EDLW (thanks @Boscomantico) with just a FPL. I was not jailed.
When I read this thread, I wonder what is most difficult to be a pilot : get your flying licence or understand how you can fly from point A to point B.
I will soon be retired, I want to share my passion with my wife (who is not at all a GA flying addict), so I will soon review my missions: flying to remote, hard to drive to, non Ryanair airfields.

Jean wrote:

I have been flying to several french airports last year. I never minded about which one was Customs enabled or not. And never was bothered. I guess I can still freely fly in UE-SHENGEN zones whiteout PPR,PN. My last flight out of Belgium flight was to EDLW (thanks @Boscomantico) with just a FPL. I was not jailed.

And you are right. The general rule still is that intra-Schengen, intra-EU flights do not require any customs/immigration.

The exceptions are NOTAMed. Like this one:

E1109/17 NOTAM
Q) LFFF/FAXX/IV/NBO / A /000/999/4750N00329E
A) LFLA
B) 2017-04-08 15:59 C) 2017-07-31 23:59
E) CUSTOMS: FOR ANY FLIGHT CROSSING A BORDER : PPR CUSTOMS COMPULSORY
REFERS CHART AD2 LFLA TXT 02

There are very few of them (one less since Colmar went back to normal)

I would ask myself the question about this one too:

B8127/16 NOTAM
Q) LFBB/FALT/IV/NBO / A /000/999/4551N00110E
A) LFBL
B) 2016-12-19 10:08 C) 2017-07-31 23:59
E) NON SKED INTERNATIONAL FLIGHTS: PPR 24HR TO AD MANAGER.

So I called AD OPS who confirm that intra-EU, intra-Schengen flights require 24 hrs prior notice (I asked specifically for a flight from Limoges to San Sebastian).

So stay away from Auxerre and Limoges if you plan a flight crossing the borders of France, or comply with the NOTAM.

Aviathor wrote:

So stay away from Auxerre and Limoges if you plan a flight crossing the borders of France, or comply with the NOTAM.

For example by doing a touch-and-go at some neighbouring airfield before you land at one of the two.

Such arrangements have existed in France but one needs to have a relationship with the staff in the tower Well, maybe not that kind of relationship, although that would probably be effective

However, the Shoreham to Pontoise scheduled service used to T&G at LFAT, so it had to be “official”.

Exactly what I wrote earlier

That is no longer so in the case of Colmar. The NOTAM changed a while back and PN is required only for extra-Schengen flights. I called OPS to verify that a while back when helping @ aart planning a flight from Spain.