We had our Ligne Residence Secondaire connected in July 2008 after speaking to a very helpful woman on the English-speaking helpline (number as above). When we arrived, FranceTelecom had already connected the line, although there was a fault, we then connected the same helpline again from the Mairie's Office, after explaining the reasons for calling from a business number (i.e. because ours was faulty) the rep was able to arrange for an engineer to call within a few days and correct the fault. We've had no trouble since.
We registered on-line at www.francetelecom.fr
and are able to effect connection and disconnection of the line over the web with no difficulties. There is a charge of around €4.65 each time you request a disconnection, but otherwise there are no hidden charges and you only pay for when you have the line switched on.
As stated above, you have to have the line connected for a minimum of one month at a time; and you have to connect the line at least once in each 12 month period. The scheme is hidden from view on the France Telecom website, but take a look at this
If you do phone FranceTelecom's English-speaking Helpline from the UK, remember to use an Over-ride provider number unless you have an international call package already, because you're likely to be in the queue for a long time - this is a really busy line. 20 minutes listening to the same recorded message is not unusual.
Good luck with this.
Simon & Steven