Nevermind - as long as mapping is correct we both have done our job here correctly, didn't we?

You can't find it because there is none, also hasn't been last year (also no one removed it), maybe even all the years you've been around. Don't believe every thought you think - your brain might trick you.
Sign 209-10 (which is not "Einbahnstraße" but "only left turn" as I wrote above) is at both exits of the parking lot - just to keep traffic around Markt counterclockwise.
Just check the facts with your own eyes and you'll see ;-).

Streetview pictures are from 2023 so you don't have to look around personally ;-).
People coming from the parking lot are not allowed to use this direction because of sign '209-10 Vorgeschriebene Fahrtrichtung links'.
But that doesn't set a status of 'formal one way' to the mentioned relation - sign 220 is still the relevant aspect.
And if one is not entering the parking lot and doing a turn on Freiberger Straße (will not happen that often but sometimes) would be legal.
Also a cyclist can put his bike at any time from the sideway on the street and go this way.

Hi Tatfahren, it's a common misconception you're stating - there is no '220 (Einbahnstraße)' sign @Freiberger Straße between 'Poststraße' and 'Markt'. Just look around or use streetview ;-) Also notice sign '286' @Aydin direction Grumbach which wouldn't be there if you weren't allowed to drive in that direction. It's a so called 'Unechte Einbahnstraße' where you are allowed to use both directions.