This small truck is called "Type H" by Citroen. It was first sold in 1947 and continued to be used for years. It is now a familiar old car in French people mind as we see it in old movies and people kind of kept a loving memory for it like. I found this one in a street used for a restaurant advertising and it is quite nicely maintained.
If you want to know more about this trucks there are websites by passioned guys but only in French I'm afraid like http://deuch.chez-alice.fr/typeh.html or http://citroenhy.free.fr/Site.htm.