For your visit several hours should be sufficient.
Distances are all walkable.
Worthy attractions: Grotte des Grandes Canalettes; Fort Libéria; ramparts; Cova Bastera; St-Jacques.
Last visit: August 2017.

Villefranche-de-Conflent is a tiny walled town that features on two important registers: It is both a member of Le Plus Beaux Villages de France and a UNESCO World Heritage site though the serial Fortifications of Vauban property.
Things to See
The town is literally two streets and one square. You will be able to step on every stretch of pavement in town in a matter of an hour. You will certainly find yourselves on the pleasant Place de l’Église, flanked by the city hall and the church of St-Jacques ♥, which is worth a look when open. You will undoubtedly step onto Saint-Pierre bridge ♥ over the Têt.
The ramparts ♥ are the basis for the town’s UNESCO recognition. While impressive from the outside, they are slightly disappointing on the inside. You get to walk long fortified passages along the walls, but there are very few good looks onto the city and, except for some historical information presented at a dozen of landings, the passage are devoid of any artifacts or decorations.
Cova Bastera ♥ is another part of fortifications, located just outside town walls. It is a cave complex adjoining a fortified chamber with porthole views over the town.
Finally, Fort Libéria ♥ is a self-contained well-preserved military installation high above town. Climbing up there will take around 20 minutes even for the most athletic. There are several points of interest inside the fort, such as barracks, service areas, and a church. The descent can be made along underground passages with over 750 steps connecting the fort and the town; from an open-air landing in the middle of descent you can get the best panoramic views over the town.
The most impressive attraction in town is located half a kilometer away from the town walls. Grotte des Grandes Canalettes ♥♥♥ is a breathtaking series of caves with thousands of stone and calcium formations, an underground lake, and a couple of chambers too grand to describe. Linger for the classical music in the main chamber.
Place to Eat
Restaurant El Patio ♥ on the main street – excellent food from presentation to taste. Épaule d’agneau was unbelievable and other dishes were just as good. The service was a bit too unhurried, and in the end some real or imagined problem with the credit card terminal (for non-French cards only) caused us to go withdraw money from an around-the-corner ATM to pay. But a nice meal otherwise. Our damage: €310 for 8 people. Last visit: Summer 2017.