Anis Asea wrote:
Then when should I book the regular tickets for it to show reservations? Also any idea where to book regular tickets from paris to barcelona for cheap. Cause based of my research regular tickets even booking them 3-4 months in advance the cheapest is around 140 euros which is insane in websites like sncf/raileurope
For reservations on Budapest-Vienna, I'd check a few weeks in advance. Maybe a month.
Paris-Barcelona is one of SNCF's cash cows. Tickets can be cheaper (I believe they start from €59) but when SNCF expect many passengers, then they don't offer such low fares.
You could look into using a TGV to southern France (Perpignan, Nîmes or Montpellier) and then regional trains via Portbou.
Alternatively, look into a pass. If you're doing enough journeys within 1 month, maybe a pass is worth it for all or some of the journeys. A sale has started today (until 1/4), with 15% discount on all passes except the one country pass for Switzerland.