(Supposed to be) a plate from Berlin, yes, the registration sticker is supposed to be a Berlin sticker. (No police vehicle, but I'm unable to read actual text in your image) Safety/emission sticker missing. Looks close enough to see what they were copying, more than adequate for a movie. Letters are not correct though. More info here, probably already read by you: https://en.wikipedia.org/wiki/Vehicle_registration_plates_of_Germany

Probably used in a movie prior to 1994 (old pre-1994 style) or set prior to 1994

No match found for your B-LR 1845

You could send user @ingo a PM (Go to 'Inbox' at the forum main page, click on 'New Topic' and you should see 'Send a private message' at the top)