For journeys from 11 December, Dutch and Belgian railways can book the TGVs between Paris and Barcelona again. That includes Interrail/Eurail reservations, which can be booked by phone or at one of their international ticket offices.
Deutsche Bahn can no longer book pass reservations for these trains for journeys from from 11 December.
I have updated the post about booking these trains.
Since last week, Belgian railways can also book reservations for French domestic night trains again. Again, pass reservations can be booked by phone or at one of their international ticket offices.
All reservations booked via Dutch or Belgian railways can be sent via email.