Paris will continue to push for a broader deal aimed at ensuring Iran complies with a landmark 2015 deal curbing its nuclear programme, "whether the United States participates or not", France's defence chief said on Tuesday.
"This agreement is not the best one in the world," Defence Minister Florence Parly told RTL radio.
"But without being perfect, it still has its virtues … and [the Iranians] are respecting it," she said.
US President Donald Trump is widely expected to announce Tuesday that he is pulling out of what he has called a "very badly negotiated" deal with Tehran and possibly reimpose economic sanctions.
France, Britain and Germany — the European signatories of the accord — have been urging the US not to back out, while agreeing that more needs to be done to curb Iran's ballistic missile development and what it calls its destabilising policies in the Middle East.
"Iran is a power that is looking to exercise its influence across the region. That is why it's involved in Syria," where it is supporting President Bashar Al Assad against opposition rebel groups, Ms Parly said.
But the Iranian presence has increased tensions with nearby Israel, which has carried out several strikes on targets in Syria in recent weeks.
"We can see that any escalation … that could lead Iran not to respect the deal that was signed, including by the United States, would only aggravate what is already a very tense situation," Ms Parly said.