You can normally rent cellphones for not too much money, but I'd be suprised if they had good international rates. What you could do is look for a calling card which you could use with your cellphone (local access number, etc) which should give you reasonable rates to the us (we pay around 4c per minute for our US calls, you should expect similar from european calling cards).

One other option might be to buy a Pay as you Go cell once you get to france. You're probably looking at around $100 for the handset initially, but you should be able to reuse it every time you're over for the tour just by topping it up with more credit when you arrive.

This has the advantage that you can get a Pay as you Go SIM card wherever you go with it (in the UK for example) and just stick it in this handset and you're set to go. :)