Remove interior door trim panel and the water shield behind it. This will surely allow you enough room to get a hand inside to grab it. Also likely harmless to ignore if you choose as it will never hurt anything.
Or try very sticky tape like duct tape on straightened out coat hanger and go fishing. Best done by the dark of the moon (reduced lighting makes your pupils dilate) and a flashlight. Use some rounded thin shins to hold the weather stripping apart a little so you can look down the crack. These can be specially made items or just use a Popsicle stick or tongue depressor. If you can see the paper and get lucky, you might save yourself from taking the door apart. Just be sure the tape is firmly attached to the coat hanger or then you’ll have to fish two items out. (Don’t ask me how I know that.) Here’s a picture of a shim my tint shop gave me and my Rube Goldberg coat hanger and Gorilla tape. I’ve had more luck with that than the flexible “grabber” that has prongs on the right.
