Illegal grape varietals in France

Whilst walking the doggo around the hills of the Charente-Limousine, an area not renowned for quality wine production, if wine production at all - Pineau des Charente isn’t really wine, it’s a fortified grape juice, which is deliciously juicy sweet with a kick of poorly integrated alcohol - I stumbled across a rather small allotment of very well-groomed bush vines.