In the old days we used to qualify concentration camp headings  by their  geographic location.  Things have gotten easier since.

We now  treat concentration camps as corporate bodies and qualify them  by the term   "(Concentration  camp)".  For examples, see  NARs n 96112360 and no 96065344.  In your 670, however,  please cite the geographic location in addition to any other pertinent information you may deem necessary)

You may still need to establish the geographic location if the  650 or 651 subject headings warrent it., e. g.,  650 Holocaust, Jewish (1939-1945)--Country--Locality.  But that is another issue.