I am not sure if you were referring to the August 1939 deportation to Zbaszyn of Polish citizens living in Germany.
You can read about it here: https://www.yadvashem.org/holocaust/this-month/august/1939.html
"On October 27, 1938, German authorities began arresting Jews of Polish citizenship living in the Reich and transporting them to the Polish border. Responding to a Polish decree that all passports of Polish residents abroad would be rescinded by the end of October unless a special permit for reentry to Poland was received, the Germans preempted the Polish government by forcibly deporting thousands of Jews across the border into Poland."
I have a relative that was deported to Zbaszyn and so far we were not able to find any trace of him. There are some documents that I found at the JDC Archive while searcing by name at https://names.jdc.org/