The webpage has many still shots and lots of video clips that illustrate the noir visual style in spy noirs.
Note that del Rio isn't a femme fatale in International Settlement. Yes, in her first scene she fires a pistol at George Sanders, when his back is turned toward her. The bullet misses, he turns around, and she's shocked to discover that he isn't the man she thought he was. She's married to Leon Ames (we learn much later), but rapidly falls in love with Sanders and saves his life (by transferring her blood into his body!). Once John Carradine kills Ames in the penultimate scene, del Rio and Sanders can and do romantically couple. It's preposterous to call her a femme fatale. One thing more, Ames is against Sanders, but del Rio does nothing on Ames's behalf; she's Sanders's ally.
The plot summary of Lancer Spy on the American Film Institute's website indicates that del Rio is a soft femme fatale.