It's in France, but you'll see some around Maidenhead (5)
I believe the answer is:
somme
'it's in france' is the definition.
('Somme' is part of 'france')
'some around maidenhead' is the wordplay.
'around' indicates putting letters inside.
'maidenhead' becomes 'm' (head letter of 'maiden').
'some' going around 'm' is 'SOMME'.
'but you'll see' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for somme that I've seen before include "Battle site in France" , "French river known from First World War" , "Scene of World War One battles" , "runner" , "WWI battle site" .)