I did not enjoy this film and predict it will not attract a mainstream audience.
Why? While the premise of a story linking people who take the train between Paris and Lisbon intrigued me initially, the story was perhaps a bit too 'real' for me. By real, this means where the content was too much like reality TV. While the shooting style was more conventional, there were cuts between scenes that seemed somewhat abrupt visually (i.e. it seemed like a scene of a single person was edited to cut out all the boring bits. The result is the 'jump' when a person is standing somewhere, then jumps to somewhere closeby, but you know it was a re-take. It works, but becomes distracting. The stories seemed very real, not heightened, and perhaps flat. As a result, nothing outstanding or interesting seemed to be told. I didn't get a sense that anything big or dramatic was happening.
Which is probably what the director was trying to do. Some very funny moments, but overall, I would give this a miss unless you have a particular interest in the cultures along the Lisbon to Paris train link. The one thing I did enjoy was the French, Spanish and Portuguese in the movie. This might be the only movie where you could hear all three languages. That was fun for me even though I didn't understand it all.