It worked to call my landline number in Paris, but not to my French mobile. I suspect you will find it only works to call cheap places. Since the going rate for calls to France is about the same as for domestic long distance, this isn't much of a bargain unless you are calling from a cell phone with flat rated domestic calls and overpriced international (quite typical for US mobiles.)
The always informative Local Calling Guide reveals that 712-858 is the tiny Superior Telephone Co-op, which strongly suggests that this is a USF arbitrage gambit. That is, the co-op gets a very high per minute settlement rate on inbound calls which is more than enough to pay the penny or so that most int'l calls cost and still have something to split.
A little poking around reveals that this isn't the only USF arbitrage in this exchange:
John