In Paris, a large centre for teens remains free (7)
I believe the answer is:
unleash
'free' is the definition.
(to unleash is to free or release)
'in paris a large centre for teens remains' is the wordplay.
'in paris a' becomes 'un' ('a' in French).
'large' becomes 'L' (eg in clothes sizes).
'centre for' indicates the central letters.
'remains' becomes 'ash' (remains of a fire).
The middle letter of 'teens' is 'e'.
'un'+'l'+'e'+'ash'='UNLEASH'
(Other definitions for unleash that I've seen before include "Let loose" , "Free from control" , "Flee from restraint, allow to pursue like dog" , "Shun ale to free from restraint" , "Release from restraint" .)