French city boundaries visited by ambassador (6)
I believe the answer is:
rheims
'french city' is the definition.
(I've seen this before)
'boundaries visited by ambassador' is the wordplay.
'boundaries' becomes 'rims' (rim is a kind of boundary).
'visited by' indicates putting letters inside.
'ambassador' becomes 'he' (His or Her Excellency).
'rims' going around 'he' is 'RHEIMS'.
(Other definitions for rheims that I've seen before include "French town" , "The Jackdaw of -- (Barham)" , "French coronation city" , "The Jackdaw of - (The Ingoldsby Legends)" , "City in NE 22 across" .)