I will echo the comments from Barslater. This is politically complex for all of being a romantic fantasy, more mature in its attitudes than the French have been since they produced it. Back in the days when I put together film programs for science fiction conventions, I tried very hard to find a rental copy to show and never could.
The film is rather more elaborate than its source material, a short story by Marcel Ayme, "The Walker Through Walls," which is ironically more easily available than the film. The film was shown on channel 13 in Baltimore, and since their massive catalog of prints (they were a DuMont station originally with a lot of time to fill) was sold the the Merican Film Instutute, it should really be available somehow.