Found this at google video: Link removed
It's in French I'm afraid and quite brief.Moderator Note: The video can be found here at the original site of the INA, the French national media archive, so the Google link has been replaced.
Also in the line-up is (I believe - in fact I'm sure) André Franquin, another leading contributor to the Belgian comics industry at the time. Franquin's "Spirou" and "Marsupilami" can be seen in the background. He is also famous for "Gaston Lagaffe".
You could describe this as a meeting of the Big Four of the French-language comics industry, whose work are still major best-sellers to this day.
It's not much of an interview. A lot of this clip appears to be about Goscinny's early career in America and how he gave up drawing for writing. One notable thing is that Herge claims that his stories are more believable, though that does not make "Asterix" any less of a major work.
Goscinny and Uderzo counter this by pointing out that Herge develops a storyline in which he includes gags, whereas they develop gags which include a storyline. Herge agrees with this.
If someone can come up with the whole interview that would be great.
Notice how, at the very start, Hergé appears almost to be a headless ghost! Some TV technicians have some answering to do!