The Roman stock market scenes were filmed on Sundays when the market was closed. Real brokers were drafted to make it more convincing.
Some US exhibitors were so perplexed by the non-verbal ending that they simply chopped off the last 7 minutes, which is now regarded as one of the seminal scenes in Michelangelo Antonioni's entire oeuvre.
The film was not a commercial success apart from in Japan, where it did very well.
To prep for the film, Michelangelo Antonioni traveled to Florence to film an actual solar eclipse. He said of this experience: "There was a silence different from all other silences, an ashen light, and then darkness - total stillness. I thought that during an eclipse even our feelings stop. Out of this came part of the idea for L'Eclisse."