Obtaining French nationality

You just go and pick up the forms at Préfecture de Police, if you are in Paris, or in any Préfecture de Département otherwise.

If you are expeditious yourself, it would take you six months.

Thanks Francis. I appreciate the advice.

Not quite as easy as you made it sound, unfortunately! I went to the Prefecture got the forms and was told it would be 18 months before I even heard back from them. Assuming all is in order it would take well over 3 years before the naturalization process is completed. I don't know if Prefectures in other Departements are equally slow but I suspect they are and certainly will be in the IDF. I live in the Essonne.
Other joys I learned is that you can't move your domicile during your application process as the address they use is the one on your Carte de Sejour and if you change addresses you have to update your CdS. Mail is only forwarded for one year by La Poste! And once your application is in you can't just advise them of a change of address, you have to start the process all over again with a copy of your new CdS. Joseph Heller would be proud of this one!
Thought I'd share this in case someone else is wondering about the process and what's entailed.

Well, I talked to people who have experience of the procedures:

Two cases that we know,

One in Seine et Marne = 11 months.
One in Paris = 2 years.

It seems that the administrations are overwhelmed and there is some delay, they have over 35 000 applications per year.