The French girl, sensitive to cash (5,6)
I believe the answer is:
legal tender
'cash' is the definition.
(thesaurus)
'the french girl sensitive' is the wordplay.
'the french' becomes 'le' ('the' in French).
'girl' becomes 'gal' (synonyms).
'sensitive' becomes 'tender' (synonyms).
'le'+'gal'+'tender'='LEGAL TENDER'
'to' is the link.
(Other definitions for legal tender that I've seen before include "That which a creditor must accept" , "Unrefusable form of currency" , "coins?" , "Official currency" , "Money which must be accepted as payment" .)