Unridden suggestion: Avenue Verte to Paris, EV3 south to the Loire, EV6 Loire à Vélo east to Paray le Monial, cut across to Mâcon, south to Lyon, Via Rhona to Avignon, east on EV8 to Nice.
I've only ridden EV6 west of there, but that was fine. There's lots written online about the Avenue Verte. If wanting to avoid Paris, V16 and V41 via Vernon to Chartres and then D roads to Orléans looks the best route on the map but no idea how it is on the ground.