I have received the same letter with the same expiration date. I did some research on the web and found out this has been going on for at least a year. Today I went to the local Caf office where the clerk showed total ignorance in front of the faultive message in the letter. And said I had to fill it in whatsoever. Finally adviced me to use my internetconnexion to mail in a demand for seeing a CAF adviser. I thought I had been behaving rather calm and correct but the clerk was stressed, arrogant and irritated, pretty unpleasant attitude. The clerk finnishes me off with "Without any earnings you can't stay in France". The clerk could at least be happy having a job paying three times more than I touch to support three persons.
Being unsatisfied with my visit I called the CAF service, wait ten minutes and pay per minute, this clerk was as nonunderstanding as the earlier, and insisted I filled in and sent over the form. I insisted on that the CAF allready have all my information and updated as well. But she then insinuated that I might have left the country and just wanted to continue lifting the RSA! "Vous comprenez Monsieur?"
I just asked for help with the rent for the new appartment we just moved in to.
I quoted a text I found on internet yesterday that confirms that "after 5 years of legal uninterrupted residence in France You obtain a permanent droit au séjour, after this period You are not any more obliged to justify your staying, working or not, You can stay definitely in France unless You present a serious threat to public order."
The clerk asked where I got this text from, and I answered truly: www.service-public.fr , silence and then goodbye.
Next move is getting a rendez-vous with an adviser. Once out of two there is a chance to be received by a decent clerk.
After my research on the web I find it under all critics that this letter continues to circulate. The text in it is not only faultive it is not even comprehensible. The CAF as organisation ows a public excuse and individual corrections for this harassements. Make a research Yourself and you will see that there are many victims from many EU countries.
I moved to France from Sweden 20 years ago, and I intend to stay.