If it's any help, my grandfather was half German, half Polish. He was captured with Wehrmacht and later joined General Anders Army (Polish).
... Otin, Ote or Autin.
Might it not be Autun?
Located about 50 km to the WSW of Dijon, Autun used to be a French military school but in the summer of 1940 it was converted in a camp for temporary lodging of prisonners awaiting transfer back to Germany.
There is an Audincourt south of Belfort in Alsace. I can't confirm that there was a POW camp there but it's in a fairly likely location.