The work by AKQA on the @LaVieOnBoard Instagram account shows a canvas of 200 images showing what it is like to be on board the new train.
The squares tell different stories using animated videos and images, including a couple falling in love and OAPs having a party while on board.
Lionel Benbassat, the marketing director at Eurostar, said: "This Instagram horizontal canvas idea has immediately seduced us.
"It allows us to discover in a playful way all the features of our new trains, and it gives users a preview of their travelling experience from London to Paris."
The campaign was created by August Ostberg, Ludwig Hallstensson and David Svedenstrom. The Swedish trio joined AKQA last year after winning the agency's global Future Lions competition in 2014 for "Google Gesture".
Peter Lund, a creative director at AKQA, said: "Launching the e320 exclusively on Instagram allowed us to bring the train to an existing community in its full length and glory.
"By using Instagram’s grid view as our canvas, we allow users to dive into the train and explore all its new features."