Nervous Man Knocking in European Comic Style

A cartoon illustration in a classic European comic book style. A bald, middle-aged man with a prominent nose and worried expression stands in front of a door with a sign reading "RADIOSCOPIE" in bold red letters. He is wearing a blue jacket, a striped tie, and bright orange trousers. His body is hunched over slightly, and his hand is raised in a knocking motion, with "Toc Toc" written above his fist, accompanied by motion lines indicating repeated knocking. The background is simple, with a white wall and a black floor. The art style is characterized by clean, bold outlines, flat colors, and exaggerated character features. The overall mood is humorous and slightly anxious, suggesting the character is hesitant or nervous about entering. The lighting is bright and even, typical of comic panel art. Medium shot, eye-level perspective.