That's the fifteenth letter from France he's got (3)
I believe the answer is:
leo
'france he's got' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'that's the fifteenth letter' is the wordplay.
'that's the fifteenth' becomes 'le' (I can't justify this - if you can you should give a lot more credence to this answer).
'letter' becomes 'o'.
'le'+'o'='LEO'
'from' is the link.
Can you help me to learn more?
(Other definitions for leo that I've seen before include "Fifth sign of the zodiac" , "Cancer, ___, Virgo" , "certain stars" , "sign of summer" , "Singer-songwriter Sayer, b. 1949" .)