The nearest airport is Perpignan, just 20km from the village of St. Genis des Fontaines. Ryanair operates seasonal routes to Perpignan.

Barcelona Girona (Spain) is very convenient, approx. 90km, 1 hour drive, many UK airlines fly to Girona
Other nearby airports are Beziers 130km and Carcassonne 150km, Montpellier 190km and Toulouse 245km and Barcelona, Spain 180km.

Car hire is readily available and can be booked directly with airlines or check airport websites for car hire quotes
A more leisurely option if you have time is to drive, or travel by train.
Eurostar via Lille or Paris and TGV train to Perpignan (8-9hrs), Montpellier (7hrs)