jon, From 22 May, SNCF in ticket offices or through SNCF Connect can no longer sell you tickets for at least these neighbouring railways (this list might not be complete)
NS 🇳🇱
SNCB 🇧🇪
SBB* 🇨🇭
Renfe 🇪🇸
Trenitalia 🇮🇹
DB** 🇩🇪
ÖBB 🇦🇹The scale of this absurd decision is amazing. And it plays right into the hands of the likes of Trainline
- except Lyria
** - except cross border FR-DE TGVs and ICEs