Is there a photo of the harpist? At that time, it could be Marie-Claire Jamet, who would have been 38 at the time, or Catherine Michel, who would have been 23, or perhaps Martine Geliot, who would have also been about 23.
I thought I posted a video link. https://www.youtube.com/watch?v=V_zvmhjXZzI
I thought Jamet, it’s a blonde, but it seems to be a different orchestra than hers. She gets a lot of sound out of what looks to be an Erard. It didn’t remind me of Nordmann, but it might be her.