True or false? In any case one of the most interesting works to read in the field

An agent out of the shadows: DGSE Action Service, Pierre Martinet
Very interesting introduction (which certainly is older) at Action Service of the DGSE. A book that reads well, like a detective story (Pierre Martinet has Roman spy edit later and it is not a coincidence), which sheds some light on the sometimes thankless profession these men of action.

25 years in the secret services, "Pierre Siramy" (Maurice Dufresse)
Interesting in the sense that this book explicitly although the administrative aspect and severity of the French secret services. This work, which is more difficult to read, is important to discover for those who consider switching administrative assistance for working Boulevard Mortier. However, this book by a former senior official leaves me a funny aftertaste because it makes me think of a way to settle scores with former colleagues some of which are explicitly named.

A life in the shadows of Thierry Jouan
Certainly the book on the DGSE me the least interested. It looks more like the result of a therapy of a former DGSE - who took the opportunity to settle accounts too - that a book on the secret services. The author gives us his feelings and has a nasty habit of punctuating his sentences for many "religious trinkets" (thank God, I pray, God will help me etc ...) which have almost ruined me the pleasure of reading (but of course it's personal).

The spy of the President, Didier Hassoux, Christophe Labbé, Olivia Recasens
Interesting point of view of the relationship that the DCRI had with the world of policy. The book is written rather moderate and appears extremely politically oriented me that does not put him in my top list of books recommended for those who sintéresseraient the secret services.

The wisdom of the spy, Alain Chouet
Excellent. Simple, well-written, easy and quick to read. The book helps to step back in this business without falling into the disclosure of open secrets or sensational.

As for Missions, methods, special techniques of secret services in the 21st century, I must admit that this is perhaps my favorite book (in this area). It is not easy to read, which is due to the impressive amount of exempt information. Like other people who have left a comment, I remain quite cautious by chapters on the influence but I wonder to what extent what is reported is true or exaggerated as the "revelations" are chilling, although some does would surprise me that half (the authors cite rarely names or facts that actually occurred but it is not complicated to make the connection).
For those who have read the book: this book is not itself an attempt to black propaganda directed against Western secret services? After all, the authors are either anonymous or they use a pseudonym (Jacques LEGER) and the contents of this book (manipulation techniques, servo, influence / propaganda) could feed some debates on freedom and Democracy ;-)
Seriously, I'd be curious to know more about the authors of this book to try to get the truth from falsehood.
Meanwhile, if skeptical I may be, I feel a little more equipped to analyze recent events related to the use of chemical weapons in Syria and in particular the dissemination to the general public on an internet portal by the Ministry of Defense declassified reports of DRM / DGSE and shocking videos. The readers of the book will see here a specific case related to the chapters of the end of the book (I am not saying here that it's wrong or it's right, I just see, at least I try to make a link between theory and practice).

Anyway, apart from some misspellings and some inaccuracies (such as in a note or footnote the author explains that the Grand Orient of France advocated atheism while not exactly the GODF that advocate the absolute freedom of conscience - major difference) I highly recommend this book.