Herb around old French bread now (4)
I believe the answer is:
euro
'french bread now' is the definition.
(French currency - bread can mean money)
'herb around old' is the wordplay.
'herb' becomes 'rue' (rue is a kind of herb).
'around' shows that the letters should be reversed in order.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'rue' written backwards gives 'eur'.
'eur'+'o'='EURO'
(Other definitions for euro that I've seen before include "EU money" , "International monetary unit" , "wallaroo" , "change in Dublin" , "International currency unit" .)