Average commercial, European, showing public procession (6)
I believe the answer is:
parade
'public procession' is the definition.
(I've seen this before)
'average commercial european' is the wordplay.
'average' becomes 'par' (average score in golf).
'commercial' becomes 'ad' (abbreviation for advertisement).
'european' becomes 'E' (abbreviation e.g. EU).
'par'+'ad'+'e'='PARADE'
'showing' is the link.
(Other definitions for parade that I've seen before include "Assembly of troops for inspection" , "Ostentation" , "Flaunt; ceremonial march" , "March-past of troops etc." , "exhibition" .)