[dcminter]

The discoverability on those things is definitely lacking. I think it took us five or so broken touch-screens before my wife noticed that you could use that to select menu options instead! I guess once you know it's fine though? Feels a bit dated compared to the typical touch & go card payments elsewhere in Europe now though.

[surfingdino]

I couldn't work it out for a good while, because it's the most unintuitive UI I have found on reasonably recent ticket machines. Once you know how to use it, it's ok.

ProTip: if you travel from London on a train, the buffet sells Paris Metro tickets.