SFR La Carte has 2 30 cents a call options, daytime weekdays or at weekends, for €5 a month each. Or there's a favourite number option with 50% off; or another with unlimited calls for a week for €4. All useful with calling card or similar access.
http://www.sfr.fr/offre-sfr/particul...carte/options/
Orange has unlimited bundle options as well, but they change these from time to time, and it isn't easy to find them on their website