German dog, red, with a round figure (7)
I believe the answer is:
hundred
'a round figure' is the definition.
(I've seen this in another clue)
'german dog red' is the wordplay.
'german dog' becomes 'hund' (I've seen this in another clue).
'hund'+'red'='HUNDRED'
'with' acts as a link.
(Other definitions for hundred that I've seen before include "Former division of county" , "Historical division of a county - number" , "Number - old part of a shire" , "Subdivision of shire; ton" , "Square number" .)