Where do you find these personalized stamps ?

Late March 2007, Dominique announced an auction on eBay : one sheet of personalized stamps. The main stamp was the commemorative "Bicentenary of the Cour des comptes" (Court of Financial Auditors) attached to personalized label for the 20th anniversary of the Regional Chambers of Financial Auditors.

This wednesday afternoon, the beginning price on 2 auctions is set at 280 euros and 400 euros the sheet of these stamps (5,40 euros of actual postal value), that are normally for the Regional Chambers mail use...

Since I am not a speculator (but I'm thinking...), I simply wrote to the Regional Chamber of Languedoc-Roussillon and asked for some advice regarding its activities. And I received this enveloppe franked by a franking machine.

Did my letter arrive after the stock of personalized stamp was exhausted ?
Did this Chamber have these stamps ?
Might I have written specifically to have these stamps ?
What are the conditions the employees received to use them ? (And were they authorized to give them to an eBay seller ?)
Worse : are the Regional Chambers the ones that made this stamps be printed by the postal printer (Phil@poste Boulazac) ?

French philately nowadays : enough questions to write a book.