P3 Templates have been designed  as a  mix  of financial information  (being the  key  metric  the GCA - Gross Carrying  amount)  and Sustainability-linked  information (such  as  CCM, CCA, alignment metrics,  etc.).  
In   some  countries  a   company  can  only  take  part  in those  activities  included  in  its founding statutes. Companies therefore  tend  to give themselves  flexibility  when selecting options, but  then   choose   for  statiscal  purposes  the  one  to  be  more  relevant  which  is known as the  statutory economic  activity.   This  classifications  can  be  extracted  from public  records (no expert  judgement  needed) and  is  unique  for each  of the  individual companies that  form part of  a consolidated  group, even the holding company has its own NACE.  
Credit  institutions  distinguish  between  the  statutory  economic  activity  ( see previous explanation )  and  the  main economic activity. The  2nd  is  , generally,  the result of  an analysis  of  the  different  sectors, economic activies or the subsidiary that best represents the whole group. Therefore  this classification relies  on  expert  judgements  by the bank´s personnel.  
Both  attributes  are generally  available in the bank´s systems. While the  references  to  FINREP are clear and must be used the direct counterparty NACE (understood as statutary) other reports as Pilar III ESG  also mention the direct counterparty NACE as well. However, for ESG Taxonomy criteria are not clear and we assume it has to be similar to Pilar 3. 
To summarize the question is whether only a NACE must be used in all the reportings (i.e. NACE statutary) or both attributes should be  used depending on the specific report. 
As the goal of the information  is  for  Pilar III & Taxonomy  disclosures  to be comparable  across credit  institutions, clear  guidance  would help  participating institutions  when fulfilling their regulatory obligations. Therefore to understand whether NACE Pilar III & Taxonomy must be the same or they could be different from the one used in FINREP in order to assurance the main activity for climate management (i.e. Paris Agreement, etc).