Could that be?
Had relations between the 2 countries so frayed in recent years that they had forsaken cooperation to bring accused persons to justice? Was the Bush-Chirac brouhaha over Iraq the cause? The protracted effort to retrieve Polanski (prior post)? The Ira Einhorn case?
None of the above.
En effet, the U.S.-France Extradition Treaty remains in effect. (photo credit) The current version (starting at page 341 of the linked document) was signed in 1996 and entered into force in 2002. It hearkens to precursor treaties, one dating to 1909.
This 1996 treaty, moreover, builds on a standard extradition-treaty template. Thus it includes: a pledge of mutual obligation to extradite fugitives in certain serious criminal matters; detailed procedures for such transfers; and exceptions from extradition, for certain offenses of a political nature, and for capital offenses absent assurances that the fugitive will not be subjected to the death penalty if convicted.
So why the initial claim that no such treaty exists?
Presumably it arose from the fact that this treaty -- again, following a template -- does not obligate either state to surrender its own national. The U.S. Executive Branch may do so "if, in its discretion, it deems it proper to do so." No mention of the French executive; as stated in a French legal dictionary,
[E]n principe la France n’extrade pas ses nationaux, mais les juge elle-même.
In principle, France does not extradite its nationals; rather, they are tried before French courts.
Thus the claim was wrong on the whole, yet right in the precise circumstance:
Had Dominique Strauss-Kahn, then but not now the head of the International Monetary Fund, not been seized from an Air France jet moments before it left for Paris 2 weeks ago, there could not have been -- as to him -- any France-U.S. extradition.