Profitable data cut in France once (7)
I believe the answer is:
gainful
'profitable' is the definition.
(similar in meaning)
'data cut in france once' is the wordplay.
'data' becomes 'info' (information).
'cut' means to remove the last letter.
'in' means one lot of letters goes inside another.
'france once' becomes 'Gaul' (historical region including modern-day France).
'info' with its final letter taken away is 'inf'.
'inf' placed inside 'gaul' is 'GAINFUL'.
(Other definitions for gainful that I've seen before include "Profitable and productive" , "Bringing in money" .)