diff --git a/test/test_readme.py b/test/test_readme.py
index 52bb794..e026fcf 100644
--- a/test/test_readme.py
+++ b/test/test_readme.py
@@ -7,7 +7,7 @@ from tiramisu import IntOption, StrOption, BoolOption, ChoiceOption, \
                      SymLinkOption, OptionDescription, Config
 
 
-def get_config():
+def get_config(has_tree=False):
     choiceoption = ChoiceOption('cmd',
                                 'choice the sub argument',
                                 ('str', 'list', 'int', 'none'),
@@ -39,18 +39,25 @@ def get_config():
                                 'expected': 'int',
                                 'action': 'disabled',
                                 'inverse': True}])
-    config = Config(OptionDescription('root',
-                                      'root',
-                                      [choiceoption,
-                                       booloption,
-                                       short_booloption,
-                                       str_,
-                                       list_,
-                                       int_
-                                       ]))
+
+    root = OptionDescription('root',
+                             'root',
+                             [choiceoption,
+                             booloption,
+                             short_booloption,
+                             str_,
+                             list_,
+                             int_
+                             ])
+    if has_tree:
+        root = OptionDescription('root',
+                                 'root',
+                                 [root])
+    config = Config(root)
     config.property.read_write()
     return config
 
+
 def test_readme_help():
     output = """usage: prog.py [-h] [-v] {str,list,int,none}
 
@@ -68,6 +75,40 @@ optional arguments:
     assert f.getvalue() == output
 
 
+def test_readme_help_tree():
+    output = """usage: prog.py [-h] [-v] {str,list,int,none}
+
+optional arguments:
+  -h, --help            show this help message and exit
+
+root:
+  {str,list,int,none}   choice the sub argument
+  -v, --root.verbosity  increase output verbosity
+"""
+    parser = TiramisuCmdlineParser(get_config(True), 'prog.py')
+    f = StringIO()
+    with redirect_stdout(f):
+        parser.print_help()
+    assert f.getvalue() == output
+
+
+def test_readme_help_tree_flatten():
+    output = """usage: prog.py [-h] [-v] {str,list,int,none}
+
+optional arguments:
+  -h, --help           show this help message and exit
+
+root:
+  {str,list,int,none}  choice the sub argument
+  -v, --verbosity      increase output verbosity
+"""
+    parser = TiramisuCmdlineParser(get_config(True), 'prog.py', fullpath=False)
+    f = StringIO()
+    with redirect_stdout(f):
+        parser.print_help()
+    assert f.getvalue() == output
+
+
 def test_readme_positional_mandatory():
     output = """usage: prog.py [-h] [-v] {str,list,int,none}
 prog.py: error: the following arguments are required: cmd
@@ -84,6 +125,38 @@ prog.py: error: the following arguments are required: cmd
     assert f.getvalue() == output
 
 
+def test_readme_positional_mandatory_tree():
+    output = """usage: prog.py [-h] [-v] {str,list,int,none}
+prog.py: error: the following arguments are required: root.cmd
+"""
+    parser = TiramisuCmdlineParser(get_config(True), 'prog.py')
+    f = StringIO()
+    with redirect_stderr(f):
+        try:
+            parser.parse_args([])
+        except SystemExit as err:
+            assert str(err) == "2"
+        else:
+            raise Exception('must raises')
+    assert f.getvalue() == output
+
+
+def test_readme_positional_mandatory_tree_flatten():
+    output = """usage: prog.py [-h] [-v] {str,list,int,none}
+prog.py: error: the following arguments are required: cmd
+"""
+    parser = TiramisuCmdlineParser(get_config(True), 'prog.py', fullpath=False)
+    f = StringIO()
+    with redirect_stderr(f):
+        try:
+            parser.parse_args([])
+        except SystemExit as err:
+            assert str(err) == "2"
+        else:
+            raise Exception('must raises')
+    assert f.getvalue() == output
+
+
 def test_readme_mandatory():
     output = """usage: prog.py [-h] [-v] --str STR {str,list,int,none}
 prog.py: error: the following arguments are required: --str
@@ -100,6 +173,38 @@ prog.py: error: the following arguments are required: --str
     assert f.getvalue() == output
 
 
+def test_readme_mandatory_tree():
+    output = """usage: prog.py [-h] [-v] --root.str STR {str,list,int,none}
+prog.py: error: the following arguments are required: --root.str
+"""
+    parser = TiramisuCmdlineParser(get_config(True), 'prog.py')
+    f = StringIO()
+    with redirect_stderr(f):
+        try:
+            parser.parse_args(['str'])
+        except SystemExit as err:
+            assert str(err) == "2"
+        else:
+            raise Exception('must raises')
+    assert f.getvalue() == output
+
+
+def test_readme_mandatory_tree_flatten():
+    output = """usage: prog.py [-h] [-v] --str STR {str,list,int,none}
+prog.py: error: the following arguments are required: --str
+"""
+    parser = TiramisuCmdlineParser(get_config(True), 'prog.py', fullpath=False)
+    f = StringIO()
+    with redirect_stderr(f):
+        try:
+            parser.parse_args(['str'])
+        except SystemExit as err:
+            assert str(err) == "2"
+        else:
+            raise Exception('must raises')
+    assert f.getvalue() == output
+
+
 def test_readme_cross():
     output = """usage: prog.py [-h] [-v] {str,list,int,none}
 prog.py: error: unrecognized arguments: --int
@@ -116,6 +221,38 @@ prog.py: error: unrecognized arguments: --int
     assert f.getvalue() == output
 
 
+def test_readme_cross_tree():
+    output = """usage: prog.py [-h] [-v] {str,list,int,none}
+prog.py: error: unrecognized arguments: --int
+"""
+    parser = TiramisuCmdlineParser(get_config(True), 'prog.py')
+    f = StringIO()
+    with redirect_stderr(f):
+        try:
+            parser.parse_args(['none', '--int'])
+        except SystemExit as err:
+            assert str(err) == "2"
+        else:
+            raise Exception('must raises')
+    assert f.getvalue() == output
+
+
+def test_readme_cross_tree_flatten():
+    output = """usage: prog.py [-h] [-v] {str,list,int,none}
+prog.py: error: unrecognized arguments: --int
+"""
+    parser = TiramisuCmdlineParser(get_config(True), 'prog.py', fullpath=False)
+    f = StringIO()
+    with redirect_stderr(f):
+        try:
+            parser.parse_args(['none', '--int'])
+        except SystemExit as err:
+            assert str(err) == "2"
+        else:
+            raise Exception('must raises')
+    assert f.getvalue() == output
+
+
 def test_readme_int():
     output = {'cmd': 'int',
               'int': 3,
@@ -124,7 +261,29 @@ def test_readme_int():
     config = get_config()
     parser = TiramisuCmdlineParser(config, 'prog.py')
     parser.parse_args(['int', '--int', '3'])
-    # assert config.value.dict() == output
+    assert config.value.dict() == output
+
+
+def test_readme_int_tree():
+    output = {'root.cmd': 'int',
+              'root.int': 3,
+              'root.verbosity': False,
+              'root.v': False}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py')
+    parser.parse_args(['int', '--root.int', '3'])
+    assert config.value.dict() == output
+
+
+def test_readme_int_tree_flatten():
+    output = {'root.cmd': 'int',
+              'root.int': 3,
+              'root.verbosity': False,
+              'root.v': False}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py', fullpath=False)
+    parser.parse_args(['int', '--int', '3'])
+    assert config.value.dict() == output
 
 
 def test_readme_int_verbosity():
@@ -138,6 +297,28 @@ def test_readme_int_verbosity():
     assert config.value.dict() == output
 
 
+def test_readme_int_verbosity_tree():
+    output = {'root.cmd': 'int',
+              'root.int': 3,
+              'root.verbosity': True,
+              'root.v': True}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py')
+    parser.parse_args(['int', '--root.int', '3', '--root.verbosity'])
+    assert config.value.dict() == output
+
+
+def test_readme_int_verbosity_tree_flatten():
+    output = {'root.cmd': 'int',
+              'root.int': 3,
+              'root.verbosity': True,
+              'root.v': True}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py', fullpath=False)
+    parser.parse_args(['int', '--int', '3', '--verbosity'])
+    assert config.value.dict() == output
+
+
 def test_readme_int_verbosity_short():
     output = {'cmd': 'int',
               'int': 3,
@@ -149,6 +330,28 @@ def test_readme_int_verbosity_short():
     assert config.value.dict() == output
 
 
+def test_readme_int_verbosity_short_tree():
+    output = {'root.cmd': 'int',
+              'root.int': 3,
+              'root.verbosity': True,
+              'root.v': True}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py')
+    parser.parse_args(['int', '--root.int', '3', '-v'])
+    assert config.value.dict() == output
+
+
+def test_readme_int_verbosity_short_tree_flatten():
+    output = {'root.cmd': 'int',
+              'root.int': 3,
+              'root.verbosity': True,
+              'root.v': True}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py', fullpath=False)
+    parser.parse_args(['int', '--int', '3', '-v'])
+    assert config.value.dict() == output
+
+
 def test_readme_str():
     output = {'cmd': 'str',
               'str': 'value',
@@ -160,6 +363,28 @@ def test_readme_str():
     assert config.value.dict() == output
 
 
+def test_readme_str_tree():
+    output = {'root.cmd': 'str',
+              'root.str': 'value',
+              'root.verbosity': False,
+              'root.v': False}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py')
+    parser.parse_args(['str', '--root.str', 'value'])
+    assert config.value.dict() == output
+
+
+def test_readme_str_tree_flatten():
+    output = {'root.cmd': 'str',
+              'root.str': 'value',
+              'root.verbosity': False,
+              'root.v': False}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py', fullpath=False)
+    parser.parse_args(['str', '--str', 'value'])
+    assert config.value.dict() == output
+
+
 def test_readme_str_int():
     output = {'cmd': 'str',
               'str': '3',
@@ -171,6 +396,28 @@ def test_readme_str_int():
     assert config.value.dict() == output
 
 
+def test_readme_str_int_tree():
+    output = {'root.cmd': 'str',
+              'root.str': '3',
+              'root.verbosity': False,
+              'root.v': False}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py')
+    parser.parse_args(['str', '--root.str', '3'])
+    assert config.value.dict() == output
+
+
+def test_readme_str_int_tree_flatten():
+    output = {'root.cmd': 'str',
+              'root.str': '3',
+              'root.verbosity': False,
+              'root.v': False}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py', fullpath=False)
+    parser.parse_args(['str', '--str', '3'])
+    assert config.value.dict() == output
+
+
 def test_readme_list():
     output = {'cmd': 'list',
               'list': ['a', 'b', 'c'],
@@ -182,6 +429,28 @@ def test_readme_list():
     assert config.value.dict() == output
 
 
+def test_readme_list_tree():
+    output = {'root.cmd': 'list',
+              'root.list': ['a', 'b', 'c'],
+              'root.verbosity': False,
+              'root.v': False}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py')
+    parser.parse_args(['list', '--root.list', 'a', 'b', 'c'])
+    assert config.value.dict() == output
+
+
+def test_readme_list_tree_flatten():
+    output = {'root.cmd': 'list',
+              'root.list': ['a', 'b', 'c'],
+              'root.verbosity': False,
+              'root.v': False}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py', fullpath=False)
+    parser.parse_args(['list', '--list', 'a', 'b', 'c'])
+    assert config.value.dict() == output
+
+
 def test_readme_list_uniq():
     output = {'cmd': 'list',
               'list': ['a'],
@@ -191,3 +460,25 @@ def test_readme_list_uniq():
     parser = TiramisuCmdlineParser(config, 'prog.py')
     parser.parse_args(['list', '--list', 'a'])
     assert config.value.dict() == output
+
+
+def test_readme_list_uniq_tree():
+    output = {'root.cmd': 'list',
+              'root.list': ['a'],
+              'root.verbosity': False,
+              'root.v': False}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py')
+    parser.parse_args(['list', '--root.list', 'a'])
+    assert config.value.dict() == output
+
+
+def test_readme_list_uniq_tree_flatten():
+    output = {'root.cmd': 'list',
+              'root.list': ['a'],
+              'root.verbosity': False,
+              'root.v': False}
+    config = get_config(True)
+    parser = TiramisuCmdlineParser(config, 'prog.py', fullpath=False)
+    parser.parse_args(['list', '--list', 'a'])
+    assert config.value.dict() == output
diff --git a/tiramisu_cmdline_parser/tiramisu_cmdline_parser.py b/tiramisu_cmdline_parser/tiramisu_cmdline_parser.py
index b79e7c4..16bbe2d 100644
--- a/tiramisu_cmdline_parser/tiramisu_cmdline_parser.py
+++ b/tiramisu_cmdline_parser/tiramisu_cmdline_parser.py
@@ -15,7 +15,7 @@
 
 
 from typing import Union, List, Optional
-from argparse import ArgumentParser, Namespace, SUPPRESS, _HelpAction
+from argparse import ArgumentParser, Namespace, SUPPRESS, _HelpAction, HelpFormatter
 try:
     from tiramisu import Config
     from tiramisu.error import PropertiesOptionError
@@ -61,6 +61,15 @@ class TiramisuNamespace(Namespace):
         return super().__getattribute__(key)
 
 
+class TiramisuHelpFormatter(HelpFormatter):
+    def _get_default_metavar_for_optional(self,
+                                          action):
+        ret = super()._get_default_metavar_for_optional(action)
+        if '.' in ret:
+            ret = ret.split('.', 1)[1]
+        return ret
+
+
 class _TiramisuHelpAction(_HelpAction):
     needs = False
     def __call__(self, *args, **kwargs):
@@ -79,6 +88,7 @@ class TiramisuCmdlineParser(ArgumentParser):
                  **kwargs):
         self.fullpath = fullpath
         self.config = config
+        kwargs['formatter_class'] = TiramisuHelpFormatter
         super().__init__(*args, **kwargs)
         self.register('action', 'help', _TiramisuHelpAction)
         self._config_to_argparser(_forhelp,
@@ -170,7 +180,7 @@ class TiramisuCmdlineParser(ArgumentParser):
             properties = obj.property.get()
             kwargs = {'help': option.doc().replace('%', '%%')}
             if option.issymlinkoption():
-                actions[option.name(follow_symlink=True)][0].insert(0, self._gen_argument(name, properties))
+                actions[option.name(follow_symlink=True)][0].insert(0, self._gen_argument(option.name(), properties))
                 continue
             if 'positional' in properties:
                 if not 'mandatory' in properties:
@@ -224,7 +234,6 @@ class TiramisuCmdlineParser(ArgumentParser):
         for args, kwargs in actions.values():
             group.add_argument(*args, **kwargs)
 
-
     def parse_args(self,
                    *args,
                    valid_mandatory=True,
@@ -236,7 +245,7 @@ class TiramisuCmdlineParser(ArgumentParser):
         except PropertiesOptionError as err:
             name = err._option_bag.option.impl_getname()
             properties = self.config.option(name).property.get()
-            if 'positional' not in properties:
+            if self.fullpath and 'positional' not in properties:
                 if len(name) == 1 and 'longargument' not in properties:
                     name = self.prefix_chars + name
                 else:
@@ -256,6 +265,8 @@ class TiramisuCmdlineParser(ArgumentParser):
                     args = self._gen_argument(name, self.config.option(key).property.get())
                 else:
                     args = key
+                if not self.fullpath and '.' in args:
+                    args = args.rsplit('.', 1)[1]
                 self.error('the following arguments are required: {}'.format(args))
         return namespaces