Look around in the river (5)
I believe the answer is:
seine
'river' is the definition.
(river in France)
'look around in' is the wordplay.
'look' becomes 'see' ().
'around' is an insertion indicator.
'see' enclosing 'in' is 'SEINE'.
'the' is the link.
(Other definitions for seine that I've seen before include "Parisian river" , "French river -- type of fishing net" , "Paris river" , "Second longest river in France" , "Paris's river" .)