diff --git a/huffman_py/Node.py b/huffman_py/Node.py
new file mode 100644
index 0000000..779bdd6
--- /dev/null
+++ b/huffman_py/Node.py
@@ -0,0 +1,76 @@
+#
+#     Sam Hadow - Huffman-py
+#     Copyright (C) 2023
+#
+#     This program is free software: you can redistribute it and/or modify
+#     it under the terms of the GNU General Public License as published by
+#     the Free Software Foundation, either version 3 of the License, or
+#     (at your option) any later version.
+#
+#     This program is distributed in the hope that it will be useful,
+#     but WITHOUT ANY WARRANTY; without even the implied warranty of
+#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#     GNU General Public License for more details.
+#
+#     You should have received a copy of the GNU General Public License
+#     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+class Node(object):
+        def __init__(self, occurrence, char, left = None, right = None):
+            # nombre d'occurence de la lettre
+            self.occurrence = occurrence
+
+            # the character
+            self.char = char
+
+            # left child
+            self.left = left
+
+            # right child
+            self.right = right
+
+            # orientation from father (0: left, 1: right)
+            self.code = ''
+
+            # node identifier (unique in a tree)
+            self.identifier = None
+
+
+        # getters and setters (private attributes)
+
+        def get_occurence(self):
+            return self.__occurence
+        def set_occurence(self, valeur):
+            self.__occurence = valeur
+        occurence = property(fget=get_occurence, fset=set_occurence, doc="Character occurences in a text")
+
+        def get_char(self):
+            return self.__char
+        def set_char(self, valeur):
+            self.__char = valeur
+        char = property(fget=get_char, fset=set_char, doc="corresponding character")
+
+        def get_left(self):
+            return self.__left
+        def set_left(self, valeur):
+            self.__left = valeur
+        left = property(fget=get_left, fset=set_left, doc="left child")
+
+        def get_right(self):
+            return self.__right
+        def set_right(self, valeur):
+            self.__right = valeur
+        right = property(fget=get_right, fset=set_right, doc="right child")
+
+        def get_code(self):
+            return self.__code
+        def set_code(self, valeur):
+            self.__code = valeur
+        code = property(fget=get_code, fset=set_code, doc="orientation from father (0: left, 1: right)")
+
+        def get_id(self):
+            return self.__identifier
+        def set_id(self, valeur):
+            self.__identifier = valeur
+        identifier = property(fget=get_id, fset=set_id, doc="node identifier")
diff --git a/huffman_py/Tree.py b/huffman_py/Tree.py
new file mode 100644
index 0000000..e69783a
--- /dev/null
+++ b/huffman_py/Tree.py
@@ -0,0 +1,101 @@
+#
+#     Sam Hadow - Huffman-py
+#     Copyright (C) 2023
+#
+#     This program is free software: you can redistribute it and/or modify
+#     it under the terms of the GNU General Public License as published by
+#     the Free Software Foundation, either version 3 of the License, or
+#     (at your option) any later version.
+#
+#     This program is distributed in the hope that it will be useful,
+#     but WITHOUT ANY WARRANTY; without even the implied warranty of
+#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#     GNU General Public License for more details.
+#
+#     You should have received a copy of the GNU General Public License
+#     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# -*- encoding: utf-8 -*-
+from huffman_py.Node import *
+
+class Tree(object):
+        def __init__(self, root = None):
+            # tree root (Node object)
+            self.root = root
+
+            # tree nodes (list of Node object)
+            self.nodes = []
+            self.gen_tree()
+
+            self.set_id()
+
+
+        # getters and setters (private attributes)
+
+        def get_root(self):
+            return self.__root
+        def set_root(self, valeur):
+            self.__root = valeur
+        root = property(fget=get_root, fset=set_root, doc="tree root")
+
+        def get_nodes(self):
+            return self.__nodes
+        def set_nodes(self, valeur):
+            self.__nodes = valeur
+        nodes = property(fget=get_nodes, fset=set_nodes, doc="nodes list")
+
+        def gen_tree(self):
+            # generate nodes list from a tree root
+            L = list()
+            L.append(self.root)
+            while len(L) > 0:
+                traitement = L.pop(0)
+                self.nodes.append(traitement)
+                if traitement.left:
+                    L.append(traitement.left)
+                if traitement.right:
+                    L.append(traitement.right)
+
+        def set_id(self):
+            # Give unique identifiers to every node in a tree
+            for i,elem in enumerate(self.nodes):
+                elem.identifier = i
+
+        def __isub__(self, node):
+            # delete node (overload -=)
+            if self.seek(node) != None:
+                self.nodes.remove(node)
+            # recursively delete children
+            if node.right != None:
+                self.__isub__(node.right)
+            if node.left != None:
+                self.__isub__(node.left)
+            return self
+
+        def __iadd__(self, tree2):
+            # Tree merge
+            # new root
+            occurrence = self.root.occurrence
+            old_root =  self.root
+            if occurrence > tree2.root.occurrence:
+                self.root = Node(occurrence, '', left = tree2.root, right = old_root)
+            else:
+                self.root = Node(occurrence, '', left = old_root, right = tree2.root)
+
+            # add new root to nodes list
+            self.nodes.append(self.root)
+
+            # add tree2 nodes
+            self.nodes += tree2.nodes
+
+            # regenerate unique identifiers
+            self.set_id()
+
+            return self
+
+        def seek(self, node):
+            for node in self.nodes:
+                if node == node:
+                    return node
+            return None