This building is called La Bastide. It is a much altered, fortified farm on the outskirts of the village of Hérépian. It guards a fording point of the river Orb where a medieval road from Béziers crosses on its way north. I believe that the projections around the tower would at one time have supported some form of battlements. On the near left corner you may be able to make out a circular balcony. I guess this dates from earlier times too.