The Walther P38 was a semi-automatic pistol used on Earth by the Germans for their military during World War II. After the war, the pistol would see service with various armed forces and police agencies.
In the holoprogram Julian Bashir, Secret Agent, Falcon's henchmen were armed with Walther P38s. (DS9: "Our Man Bashir") In another run of the program, Falcon wielded this weapon when he snatched a female hitchhiker from Julian Bashir at gunpoint. (DS9: "A Simple Investigation")