Source of article dividing French region (10)
I believe the answer is:
provenance
'source' is the definition.
(eg the provenance of an antique)
'article dividing french region' is the wordplay.
'article' becomes 'an' (indefinite article).
'dividing' is an insertion indicator (inserted letters divide the word).
'french region' becomes 'provence' (I've seen this before).
'an' going inside 'provence' is 'PROVENANCE'.
'of' acts as a link.
(Other definitions for provenance that I've seen before include "Source of painting" , "Origin of" , "Documented history" .)