Two weeks in France from USA

[inquisitor]

Have a look at United Mobile+. They charge € 0.29 (=$ 0.45) for texts and € 0.29/min (=$ 0.45/min) + a call-setup-fee of € 0.25 (=$ 0.38 ) for calls to the US and incoming calls are completely free in whole Europe and many other countries in the world (e.g. New Zealand, Australia).
Customers get a British mobile number, which should be cheaper to call from the US than a French mobile number. Another advantage against a French prepaid SIM is, that United Mobile+ roams on all three French GSM networks, so if there's any dead zone in a certain network's coverage, you daughter's phone will switch to another network, which a local SIM can't (French operators don't have national roaming agreements, like Americans have).