Peter Labuza’s review published on Letterboxd :
Lang's films are architectural first, filtered through the cavernous mazes. Narrative then either traverses through either characters who can see much more than anyone else around them (Dr. Mabuse; Dietrich and her Notorious Ranch), or those who fail to see the cogs around them (literally in Metropolis; the criminal structures of The Big Heat). The Blue Gardenia, which Danny Kasman recently compared to Fincher's Gone Girl, deals with a character who strays from outside the world she knows into the cogs of Los Angeles. It starts out with that titular Chinese Restaurant, a place of mysterious romance and hidden spaces, as well as a soulful singer (Nat King Cole!) providing the prophetic doomed romance ("I lived for an hour/What more can I tell/Love bloomed like a flower/Then the petals fell."). That Anne Baxter's moral decision to play loose (with Raymond Burr, natch) ends poorly is no surprise, but the film then oscillates from her own guilt of the murder and Richard Conte's newsman search for the truth.
Like many Lang films, one of the key concerns is technology; here being the media and its permutations, mistakes, and eventual truth. Telephones play a central role in mistaken identify. Newspaper columns play up the suspense and the desire for suspense (Ingenue Jeff Donnell of In A Lonely Place plays the doe-eyed roommate that devours murderous pulp novels). And in the end, it is a recording that leads to the truth (of Wagner!). All in this plays into the moral seriousness of the film that so convinces us that Baxter has (justifiably*) murdered Burr. In a way, the film is M from the other perspective: a woman who can't prove her own innocence who hides from the technological society. Even Conte's little black book is a very Langian touch of reducing personalities down into numbers (more connection to Fincher, Danny!) The solution is a bore, but as Tom Gunning notes, the the subplot deals with the same issues of telephones and miscommunication as the rest of the film, so perhaps its not so silly after all.
*That the film doesn't see Burr's attempted rape as justification for Baxter's self defense is a frustrating period marker.