Help!!! 3G Mobile Broadband when visiting France

I am visiting France for a family holiday but would really like to be able to stay online while I am away, I have been looking around for the best way to get 3G access but it seems it is going to be a very expensive thing to do. I have a 3 USB Modem and they have no roaming agreements so would charge £3.00 per MB for data which is very very expensive. Does anyone have any cheaper solutions or is it possible to get a pre-pay mobile broadband set up while I am in France, my information is that you can only get mobile broadband in France by signing a 12 month minimum contract which doesn’t help. If anyone has any solutions or suggestions please leave a comment. Thanks