return RedirectToRoute("SomeRouteName", new {
culture = cultureName,
id = id,
productName = productName
});
and your route definition:
routes.MapRoute(
"SomeRouteName",
"{culture}/{id}/{productName}",
new { controller = "Home", action = "Index" }
);
Notice that the pattern of the route is {culture}/{id}/{productName}
where you need to specify each token when calling RedirectToAction. Since you have only one action in this controller you don't need to specify it. It is defined in your route.