University with nuclear research facility in the French city (7)
I believe the answer is:
lucerne
'city' is the definition.
(Swiss city)
'university with nuclear research facility in the french' is the wordplay.
'university' becomes 'u' (abbreviation for university).
'with nuclear research facility' becomes 'cern' (I can't justify this - if you can you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'the french' becomes 'le' ('the' in French).
'u'+'cern'='ucern'
'ucern' inserted inside 'le' is 'LUCERNE'.
Can you help me to learn more?
(Other definitions for lucerne that I've seen before include "Fodder plant - lake" , "Swiss city/lake" , "Place beside lake" , "Forage crop" , "ake" .)