French city badly walled by the French (5)
I believe the answer is:
lille
'french city' is the definition.
(I know that Lille is a metropolis)
'badly walled by the french' is the wordplay.
I cannot quite understand how this works, but
'badly' could be 'ill' (eg in ill-advised) and 'ill' is located in the answer.
'the french' could be 'le' ('the' in French) and 'le' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for lille that I've seen before include "Stop before Paris" , "[FRANCOPHOBIA] would prevent you appreciating it" , "N. French city" , "University city in French Flanders" , "City of N. France" .)