Yes, there are! For example, I have travelled between Strasbourg and Basel (Switzerland) on a regional train, as well as between Milan and Nice, and between Nice and Barcelona (changing trains at the Spanish border due to the change of rail gauge). There's also a regional line connecting Barcelona and Puigcerdà (a town in the Spanish Pyrenees) which at certain times continues its service a further ~5km and terminates in Latour-de-Carol, a tiny village on the French side which is served by French regional services.
