Where? I know plates containing 'SS' are illegal/not issued in The Netherlands, but also in France (SIV)? Yes, in the SIV system, and in Germany. ESS wasn't issued at us too.
As well as 'NS', 'SA', 'HJ', 'KZ', several codes in Stuttgart and Nuremberg, WAF-FE (weapon, gun) and IZ-AN (Nazi backwards).