I recently reviewed the telecommunication options for those traveling in France. Among the companies offering service in Europe (including Callineurope and Mobal) the following are my recommendations. Unlike the better known plans there are no set up fees with the following and per minute costs are minimal.
Consider either of these two options:
1. If you have an unlocked, GSM tri or quad band phone, purchase a Breizh SIM from PhoneHouse. Cost is 6.90€. Minutes are sold prepaid in increments of 5€. 52 minutes for 10€ or .19€/min. This rate applies to calls made to either other mobile phones or fixed line phones. There is never a charge for inbound minutes.
Note: Recent reports have indicated Phonehouse no longer sells this SIM, at least not from its Paris stores. It is still available via internet sales from Breizh.
2. If you do not have an available GSM phone, purchase one for 29€ ($41) from Virgin (stores all over France). There is no setup fee and it comes with a SIM and 12 free call-out minutes. Additional minutes available in increments of 5€ and charged at .27€/minute. There is no charge for inbound calls.

Updated 7 Nov 09