diff --git a/higra/algo/horizontal_cuts.py b/higra/algo/horizontal_cuts.py
index fef6b3a5..35b99231 100644
--- a/higra/algo/horizontal_cuts.py
+++ b/higra/algo/horizontal_cuts.py
@@ -77,20 +77,23 @@ def __labelisation_leaves(self, tree, leaf_graph, handle_rag=True):
     return labels
 
 
-# @hg.extend_class(hg.HorizontalCutExplorer, method_name="__new__")
-# def __make_HorizontalCutExplorer(cls, tree, altitudes):
-#     """
-#     Creates an horizontal cut explorer for th given valued hierarchy.
-#
-#     Altitudes must be increasing
-#
-#     :param tree: input tree
-#     :param altitudes: tree nodes altitudes
-#     :return: an ``HorizontalCutExplorer``
-#     """
-#     return cls._make_HorizontalCutExplorer(tree, altitudes)
-#
-#
-# @hg.extend_class(hg.HorizontalCutExplorer, method_name="__init__")
-# def __dummy_init_HorizontalCutExplorer(*_):
-#     pass
+@hg.extend_class(hg.HorizontalCutExplorer, method_name="__new__")
+def __make_HorizontalCutExplorer(cls, tree, altitudes):
+    """
+    Creates an horizontal cut explorer for the given valued hierarchy.
+
+    Altitudes must be increasing
+
+    :param tree: input tree
+    :param altitudes: tree nodes altitudes
+    :return: an ``HorizontalCutExplorer``
+    """
+    if not hg.test_altitudes_increasingness(tree, altitudes):
+        raise ValueError("'altitudes' must be increasing for 'tree'.")
+
+    return cls._make_HorizontalCutExplorer(tree, altitudes)
+
+
+@hg.extend_class(hg.HorizontalCutExplorer, method_name="__init__")
+def __dummy_init_HorizontalCutExplorer(*_):
+    pass
diff --git a/higra/algo/py_horizontal_cuts.cpp b/higra/algo/py_horizontal_cuts.cpp
index c4874392..670a3577 100644
--- a/higra/algo/py_horizontal_cuts.cpp
+++ b/higra/algo/py_horizontal_cuts.cpp
@@ -67,10 +67,10 @@ struct def_horizontal_cut_explorer_ctr {
     template<typename type, typename C>
     static
     void def(C &c, const char *doc) {
-        c.def(py::init(
+        c.def_static("_make_HorizontalCutExplorer",
                 [](const typename c_t::tree_type &tree, const xt::pyarray<type> &altitudes) {
                     return c_t(tree, altitudes);
-                }),
+                },
               doc,
               py::arg("tree"),
               py::arg("altitudes"));
@@ -92,15 +92,7 @@ Each cut of the hierarchy can be accessed through:
   - the altitude of the cut. This operations runs in :math:`\mathcal{O}(k*\log(n))`, with :math:`k` the number of regions in the retrieved cut.)"""
     );
     add_type_overloads<def_horizontal_cut_explorer_ctr<class_t>, HG_TEMPLATE_NUMERIC_TYPES>
-            (c,
-             R"(Create an horizontal cut explorer for the provided valued hierarchy.
-
-Altitudes must be increasing
-
-:param tree: input tree
-:param altitudes: tree nodes altitudes
-:return: an ``HorizontalCutExplorer``
-)");
+            (c,"");
     c.def("num_cuts", &class_t::num_cuts, "Number of horizontal cuts in the hierarchy.");
     c.def("num_regions_cut",
           &class_t::num_regions_cut,
diff --git a/test/python/test_algo/test_horizontal_cuts.py b/test/python/test_algo/test_horizontal_cuts.py
index 8516aaf2..814c31a5 100644
--- a/test/python/test_algo/test_horizontal_cuts.py
+++ b/test/python/test_algo/test_horizontal_cuts.py
@@ -35,6 +35,12 @@ def test_horizontal_cut_explorer_indexed(self):
             self.assertTrue(np.all(np.sort(c.nodes()) == np.sort(cut_nodes[i])))
             self.assertTrue(c.altitude() == alt_cuts[i])
 
+    def test_horizontal_cut_explorer_assert(self):
+        tree = hg.Tree(np.asarray((5, 5, 6, 6, 7, 7, 7, 7)))
+        altitudes = np.asarray((0, 0, 1, 0, 0, 2, 1, 1))
+        with self.assertRaises(ValueError):
+            hch = hg.HorizontalCutExplorer(tree, altitudes)
+
     def test_horizontal_cut_explorer_altitudes(self):
         tree = hg.Tree((11, 11, 11, 12, 12, 16, 13, 13, 13, 14, 14, 17, 16, 15, 15, 18, 17, 18, 18))
         altitudes = np.asarray((0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 3, 1, 2, 3))