What's the Deal With French Announcers?

From the "things no one else could possibly care about" file: every time I see an old French movie that includes narration -- and quite a lot of them do -- I'm surprised by the dry, clipped, fast-talking style adopted by all the narrators, whoever they are, and whatever kind of movie it is. The first time I saw Jules and Jim I wondered why the narrator sounded like he was bored with the whole thing and wanted to spit out the words as fast as possible. Then I saw Truffaut's Two English Girls, a similar but not-nearly-as-good movie (from a novel by the author of Jules and Jim), and the narrator, in this case Truffaut himself, was doing the same thing, talking a mile a minute in what sounded to my Anglophone ears like a monotone.

Since then I have noticed this in voice-over narration in French movies and in French-dubbed versions of English-language movies. I don't think that style of voice-over announcement is quite so prevalent anymore (another victim of globalization and its smoothing-out of national quirks?), but it's very noticeable in anything from the '40s, '50s or '60s. It's not like the much-parodied BBC announcer style; that's certainly clipped and reserved, but English announcers didn't talk nearly as fast and attempted to modulate their voices, albeit subtly. French announcers often sound like auctioneers. I really have no idea where this style comes from, but it's kind of endearing.