Protester from Germany isn't welcoming party (9)
I believe the answer is:
dissident
'protester' is the definition.
(synonyms)
'germany isn't welcoming party' is the wordplay.
'germany' becomes 'd' (international vehicle registration code).
'welcoming' indicates putting letters inside (in sense of 'inviting in').
'party' becomes 'side' (I've seen this before).
'isnt' placed around 'side' is 'issident'.
'd'+'issident'='DISSIDENT'
'from' is the link.
(Other definitions for dissident that I've seen before include "Person opposing official policy" , "Rebel, protestor" , "One opposed to official policy" , "One opposing official policy" , "Opposer of official line" .)