"The defiant attitude adopted by the Iranian government now leaves us no other choice: we have to seek new sanctions," Kouchner told the French Senate.
"We will continue to seek dialogue but what responses have we got so far? Nothing tangible," he said, adding that Tehran's nuclear programme did not have "credible" civilian goals as claimed by the Islamic Republic.
France, the United States and others are stepping up efforts to rally support for fresh United Nations sanctions on Iran, which key world powers suspect is trying to make a nuclear weapon.
Tehran insists its uranium-enrichment activities are aimed at generating power for civilian use.
Kouchner said Iran had increased the range of its missiles, was not cooperating sufficiently with the UN nuclear watchdog and had spurned "all our offers of dialogue and cooperation."
The minister also hit out at North Korea, which alarmed the world last year by test-firing a series of missiles after walking out of disarmament talks with global powers, including the United States, Japan and South Korea.
He said Pyongyang "not only threatens regional peace and stability" but also "exports … insecurity … especially in the Near and Middle East."
Countries making up the so-called "P5-plus-1" trying to rein in Iran's nuclear ambitions — the five veto-wielding UN Security Council members Britain, China, France, Russia and the United States; plus Germany — have become increasingly alarmed at Tehran's intransigence.
A UN Security Council vote on a resolution increasing economic sanctions against Iran's leadership and Revolutionary Guard is expected within weeks.
For sanctions to be approved, nine of the 15 Security Council members — including all five permanent members — have to vote for them.
Of the permanent members, China still opposes new sanctions and Russia remains reluctant.
