Solution : https://service.sap.com/sap/support/notes/303531 (SAP Service marketplace login required)
Key words : 
field/structure i_var_class_type        klah-klarti_root_object_key       inob-objeki_cucp_object_table     inob-obtabi_cucp_profile_number   cuco-zaehli_aennr                 rmclf-aennr1i_datuv                rmclf-datuv1                     tables, field/structure i_var_class_type   klah-klarti_var_class        klah-classi_characteristic   cabn-atnami_aennr            rmclm-aennri_datuv            rmclm-datuv                     tables, field/structure i_var_class_type     klah-klarti_root_object_key    inob-objeki_cucp_object_table  inob-obtabi_aennr              rmclf-aennr1i_datuv              rmclf-datuv1                     tables, function 'tools -> abap workbench' -> function 'utilities -> enhancements -> project management', create customer enhancement cucpdel1 transaction smod create enhancement cucpdel1            attributes, table parameter           reference structure configured_objects_cbase  ibin                     exception, classification data lo-vc view cbase                     components, transaction se37            create function module, enter sap enhancements 'cucpdel1', inob / kssk / ausp
Related Notes : 
       
| 304677 | Check performance of deletion function ECM | 
| 211013 | Deleting classification data w. ECM as of Rel. 4.5B | 
| 166530 | @3Z@ Config. objects delete classification data | 
| 151190 | SAP enhancement deletes classification data LO-VC |