There’s nice running in Le Barcarès, a small coastal town on the Mediterranean, combining waterfront promenades, a marina, and a pine forest. There are four ‘sections’ along the nearly 8 km one-way route, so do it all or choose a part. 

Av. du Rousillon

At the north end, start with the waterfront promenade along Al. des Arts, for ~ 2km. There are nice views of the beach & water. Then run for ~1 km through the Pine Forest (La pinède aux écureuils), on shaded paths or along the wide, tree-lined Av. du Rousillon. Continue south for 2 km on paths around an attractive port/marina area, which has nice views of water & boats. The final ~2 km is on a path alongside the wide, sandy Barcarès Beach. Note: Beach is not great for running.