As usual in France, the aeronautical publication is not entirely clear, but in the narrow sense, this must be customs, not immigration.
It joins many other smaller airfields relatively close to the Swiss border.
Taken note of @boscomantico, thanks.
But for the moment some of the Swiss based fleet prefers the 12h PPR of LFSP (and the 0.00€ landing/handling/massage fee), or the 2h PN of LFLI (and around 10€ ld fee) when out westbound or southwestbound.
But we’ll sure keep that one on the list too 
Great to hear, thanks to Bosco for the update.
Also back again with customs for intra-Schengen and EU-flights, since march 2023 is Nancy Essay LFSN. 24hr PN explicitely stating Switzerland as well as Norway and Island:
FLIGHT WITHIN SCHENGEN outside UE (Norway, Switzerland, Island) : Authorized under conditions of franchises (funds and merchandises). PN 24 HR to CODT METZ codt- [email protected]
Form available on AD operator website.
- FLIGHT OUTSIDE SCHENGEN or OUTSIDE EU : Prohibited.
Nancy is a lovely town, was always worth a visit for Swiss pilots until they dropped customs at LFSN a couple of years ago.
Montbeliard and Besancon are also 12h. But yes, nothing beats Pontarlier for simplicity.
The fact that they still designate customs aerodromes means that they unfortunately still do care about these things. Even if some people have recently reported having received the ok (after due PN) for landings from CH at totally non-customs aerodromes as well.
