The main problem is the choice of the lead:he is supposed to be a philosophy student and Fernand Gravey was 38 when he made this movie.It is impossible to believe he is a young romantic lead (Jean-Pierre Aumont or Louis Jourdan would have been better in such a part).
All that remains is original,inventive,and it is probably Marcel Lherbier's best talkie.After his brilliant silent works,his career had its highs (this movie,"le Mystere de la Chambre Jaune","le Bonheur","l'Affaire du Collier de la Reine") and its lows (dreadful melodramas such as "l'Enfant de l'Amour",les Hommes Nouveaux","la Porte du Large" or stodgy propaganda films such as "Entente Cordiale"). Ten years before René Clair's "les Belles de Nuit" ,Lherbier tells a tale of a dreamer :a student who is forced to work in "les Halles" and dreams his life away.It was the Occupation time in France and escapist works were par excellence the prevailing genre(along with "moral'" melodramas such as "le Voile Bleu" ): 1942 also brought Marcel Carné's "les Visiteurs du Soir" and the following year Delannoy-Cocteau's "l'Eternel Retour" .You could even call Gremillon's work "le Ciel est à Vous" an escapist film:a woman who had a dream to fly.
"La Nuit Fantastique" is a movie of its time.Certain of its aspects are dated ,but its best moments are still impressive today.The student meets a woman in his dreams :she will be nothing like he pictured her to be and he can never see her face;in real life,his lover cheats on him with one of his so-called pals.
One night,he "enters " his dream .The gap between dream and reality is brilliantly rendered:using time warp,masterfully working on the pictures (fuzziness) and on the soundtrack (sometimes the words become incomprehensible),Lherbier builds a sensational dreamlike atmosphere.And by introducing magic and conjurers,he gives his movie a fourth dimension.Melodrama is also present (Who is really Irene?)but it is kept to the minimum.Perhaps the final is a bit disappointing but it might have inspired Jean Cocteau for the last picture of his celebrated "la Belle et la Bête".Anyway "la Nuit Fantastique" is sometimes close to a fairy tale too ,with a smart use of Tom Thumb;and the scene on the roof recalls Andersen's "the shepherdess and the sweep" which Grimault/Prevert transferred to the screen as "le Roi et l'Oiseau"
One should also note that Lherbier's movie was made five years before "the secret life of Walter Mitty" a movie which borrows some ideas from it (making the hero out to be a lunatic ;here,the heroine)
"You can be brave when you know you are dreaming" the hero says.