Agreements from Spain about the French area in part of Europe (7)
I believe the answer is:
silesia
'part of europe' is the definition.
(I've seen this before)
'agreements from spain about the french area' is the wordplay.
I cannot really understand how this works, but
'spain' could be 'es' (es is an abbreviation for Spain) and 'es' is found in the answer.
'about' could be 'a' (abbreviation in Chambers) and 'a' is present in the answer.
This explanation may well be incorrect...
'in' acts as a link.
(Other definitions for silesia that I've seen before include "European region" , "part of Europe" , "Polish area" , "Region of central Europe" , "Central European area" .)