Did France scuttle an imminent deal with Iran on nuclear materials? Whether or not this is actually the way things went down, France seems to be eagerly claiming the role of spoiler. Fabius personally inserted himself into the negotiations when he learned that John Kerry would be going to Geneva, and, as Le Monde writes the story, he did so because he feared that an agreement was imminent. His main concerns were the heavy water reactor at Arak, which can make plutonium, and Iran's stock of 20% enriched uranium. Neither of these problems is new, however, so in essence the story that the French are putting out is that the US was prepared to accept guarantees on these two issues that France considers to be insufficient or unacceptable. That's a bold claim, and in the absence of further details, I find it rather suspect.
In any case, Fabius has succeeded in establishing France's independence, which is always an important French desideratum in foreign-policy negotiations. Whether France has any goals beyond establishing its independence remains to be seen. Of course it's possible that the deal was a bad one that the US was willing to accept simply for the sake of a deal. Nevertheless, granting Rohani some reward for his flexibility might be a way of strengthening his position at home, which is a necessary prerequisite to further concessions. The French appear to believe, however, that any weakening of sanctions will only lessen the pressure that has produced the first steps toward a resolution of the conflict. Fabius seems determined to hang tough. Let's hope he knows what he's doing.