I don't know the origin of this video (amateur edited, La Poste official film,...) but it summarized the evolution of the definitive stamp design of France since 1849:
22 June 2008 update:
As Dominique wrote on the Blog philatélie, on 22 June 2008, this video was viewable at the Salon du timbre, Paris 2008 stamp show. Very certainly a La Poste's video. A guess: was it part of the pressbook to present the new Marianne of Nicolas, last January 2008, when the design was made public?