Partners with stake in French city (6)
I believe the answer is:
nantes
'french city' is the definition.
(I've seen this before)
'partners with stake' is the wordplay.
'partners' becomes 'ns' (North and South are partners in the game bridge).
'with' is an insertion indicator.
'stake' becomes 'ante' (anteing is a kind of staking).
'ns' going around 'ante' is 'NANTES'.
'in' acts as a link.
(Other definitions for nantes that I've seen before include "Western French port" , "in Pays de la Loire?" , "French FC" , "Port city on the Loire estuary" , "port abroad" .)