A French congregation spread out (6)
I believe the answer is:
unfold
'spread out' is the definition.
(synonyms)
'a french congregation' is the wordplay.
'a french' becomes 'un' ('a' in French).
'congregation' becomes 'fold' (as in welcoming someone into 'the fold').
'un'+'fold'='UNFOLD'
(Other definitions for unfold that I've seen before include "Reveal - clarify" , "Tell" , "Spread out or become known" , "Ensue; straighten" , "Open out or reveal gradually" .)