The Iranians want sanctions to be lifted immediately,” Laurent Fabius told Europe 1 radio station.
"We say to them: we will ease the sanctions as you respect what you have agreed to and if you don’t live up to your commitments, of course we can return to the situation we had before, AFP reported him as having said.
"On this point, there is not yet a deal,” said Fabius.
Fabius spoke after Thursday’s agreement aimed at curbing Iran’s nuclear drive, hailed by negotiators as "historic.”
Under the framework, Iran agreed to sharply curtail its nuclear program in return for the lifting of sanctions that have crippled the country’s economy.
France, which presents itself as one of the more hawkish of the world powers negotiating the deal, has warned that sanctions will be reimposed if Tehran fails to live up to its side of the bargain.
"We are going in the right direction … but we are not yet at the end of the road,” stressed Fabius.
The main outlines agreed after eight days of talks that sometimes went through the night in the Swiss city of Lausanne now have to be finalized in a highly complex agreement by June 30