"If you're going to come here, learn to speak the language", appears to be the message here as it has been claimed that booking a train from Paris to Barcelona will cost more if you book on non-French or Spanish websites - essentially penalising customers for not speaking the 'correct' languages.
Train nerd The Man in Seat 61 alleges that if you go to the French train operator SNCF's website and click on the British flag so that you can book tickets in English (or the German flag to book in German, etc), you'll be redirected to country-specific websites like uk.voyages-sncf.com. Then when you search for the same journey as you would do on the French language version, it comes out costing a lot more money.
While train ticket prices often fluctuate based on demand and timing (a bit like booking plane tickets), the Man in Seat 61 is fairly confident that there is a deliberate discrimination going on as for example, on a Paris->Barcelona train on the French website it comes to €59, but on the English language website comes to €100 with exactly the same timing/etc.
At the moment, this discriminatory pricing only appears to affect the France-Spain high speed (TGV) route - hence why French and Spanish customers appear to be getting a discount, but it could set a depressing precedent for buying international train tickets. Seat 61 is also speculating that this could conceivably be in breach of EU rules, as the continent is supposed be one big single market.
The Man in Seat 61 isn't happy, saying that, "I have not seen discrimination on this scale by any European train operator before, and against other EU member states, too. From the start, I don't think the pricing on the relatively new Paris-Barcelona TGV route has been properly managed. Fares appear set with total disregard for those of competing airlines and indeed it's often significantly cheaper to buy two separate train tickets, Paris-Perpignan and Perpignan-Barcelona for the same train. After this latest example of mismanagement, it's my professional opinion that Renfe-SNCF seriously needs to replace their Elipsos pricing manager, and soon. The Paris-Barcelona TGVs need fresh eyes and competitive, dynamic pricing worthy of the 21st century. Not desperate Machiavellian tactics worthy of the 16th."
I've reached out to SNCF for a response and will update this post if they get back to me. [Seat 61]
Update (11:49): SNCF have indeed got back to me, with the following statement:
"‘As a ticket retailer and distributor, Voyages-sncf.com has access the same fares as other retailers. Following the feature on Seat61.com and your enquiry this morning, we have followed up with the carrier regarding the anomaly and they believe that there could be an error in the pricing. They will be investigating further and will revert to you as soon as possible with a fuller response. Thank you for the warning!’"
So fingers crossed the French train operator will be showing us Brits some fraternité soon.