diff --git a/include/GooseEYE/GooseEYE.h b/include/GooseEYE/GooseEYE.h
index f8389beb..ba207944 100644
--- a/include/GooseEYE/GooseEYE.h
+++ b/include/GooseEYE/GooseEYE.h
@@ -799,7 +799,7 @@ class ClusterLabeller {
 /**
  * Compute clusters and obtain certain characteristic about them.
  */
-class Clusters {
+class [[deprecated]] Clusters {
 public:
     Clusters() = default;
 
@@ -825,6 +825,9 @@ class Clusters {
     template <class T, class S>
     Clusters(const T& f, const S& kernel, bool periodic = true) : m_periodic(periodic)
     {
+        GOOSEEYE_WARNING_PYTHON("Clusters is deprecated, use ClusterLabeller (new API) instead "
+                                "(please open a PR for missing functions)");
+
         static_assert(std::is_integral<typename T::value_type>::value, "Integral labels required.");
         static_assert(std::is_integral<typename S::value_type>::value, "Integral kernel required.");
 
diff --git a/python/GooseEYE/__init__.py b/python/GooseEYE/__init__.py
index b6abe0a5..0bae7bc9 100644
--- a/python/GooseEYE/__init__.py
+++ b/python/GooseEYE/__init__.py
@@ -23,7 +23,7 @@ def ClusterLabeller(shape, periodic=True, **kwargs):
         if periodic:
             return ClusterLabeller2p(shape, **kwargs)
         return ClusterLabeller2(shape, **kwargs)
-    raise NotImplementedError
+    raise NotImplementedError("3d extension needed, please open a PR")
 
 
 class Structure(enstat.static):