The Haute Route Pyrenees (HRP) follows the French and Spanish border, we started in Lescun and ended in Garvarnie. I made also a video on my 6 day hike trip: https://www.youtube.com/watch?v=PICcWp3CGcA :
The Complete Guide to Camping on the Walker's Haute Route — The Hiking Club
Wild camping vs. bivouacing. And where is it allowed?
Europe's best mountain campsites | Camping holidays | The Guardian
The Complete Guide to Camping on the Walker's Haute Route — The Hiking Club
The Walker's Haute Route: Unguided, Unmapped and with a Tent – Meandering Mayans