Basic fixed line runs 15€ a month from France Telecom. Mobile service starts at about 20€ a month for 1 hour of calling, more with fancy services (data, etc.) - though there is always the option of buying time rather than a subscription. Internet service (ADSL) is usually available for anywhere from 20 to 35 or 40€ a month, depending on speed, volume and whether you want tv and VOIP (telephone) with that.
Cheers,
Bev