diff --git a/commitizen/config/__init__.py b/commitizen/config/__init__.py
index 2cbd544825..e4e414437c 100644
--- a/commitizen/config/__init__.py
+++ b/commitizen/config/__init__.py
@@ -28,8 +28,8 @@ def read_cfg() -> BaseConfig:
 
         _conf: Union[TomlConfig, JsonConfig, YAMLConfig]
 
-        with open(filename, "r") as f:
-            data: str = f.read()
+        with open(filename, "rb") as f:
+            data: bytes = f.read()
 
         if "toml" in filename.suffix:
             _conf = TomlConfig(data=data, path=filename)
diff --git a/commitizen/config/base_config.py b/commitizen/config/base_config.py
index f3e0767dd2..76cd1706e1 100644
--- a/commitizen/config/base_config.py
+++ b/commitizen/config/base_config.py
@@ -31,5 +31,5 @@ def update(self, data: dict):
     def add_path(self, path: Union[str, Path]):
         self._path = Path(path)
 
-    def _parse_setting(self, data: str) -> dict:
+    def _parse_setting(self, data: Union[bytes, str]) -> dict:
         raise NotImplementedError()
diff --git a/commitizen/config/json_config.py b/commitizen/config/json_config.py
index fbf37bbd83..725e37a0eb 100644
--- a/commitizen/config/json_config.py
+++ b/commitizen/config/json_config.py
@@ -6,7 +6,7 @@
 
 
 class JsonConfig(BaseConfig):
-    def __init__(self, *, data: str, path: Union[Path, str]):
+    def __init__(self, *, data: Union[bytes, str], path: Union[Path, str]):
         super(JsonConfig, self).__init__()
         self.is_empty_config = False
         self._parse_setting(data)
@@ -22,7 +22,7 @@ def set_key(self, key, value):
         For now only strings are supported.
         We use to update the version number.
         """
-        with open(self.path, "r") as f:
+        with open(self.path, "rb") as f:
             parser = json.load(f)
 
         parser["commitizen"][key] = value
@@ -30,7 +30,7 @@ def set_key(self, key, value):
             json.dump(parser, f)
         return self
 
-    def _parse_setting(self, data: str):
+    def _parse_setting(self, data: Union[bytes, str]):
         """We expect to have a section in .cz.json looking like
 
         ```
diff --git a/commitizen/config/toml_config.py b/commitizen/config/toml_config.py
index a9b3cfab1e..27ab47d4e2 100644
--- a/commitizen/config/toml_config.py
+++ b/commitizen/config/toml_config.py
@@ -7,7 +7,7 @@
 
 
 class TomlConfig(BaseConfig):
-    def __init__(self, *, data: str, path: Union[Path, str]):
+    def __init__(self, *, data: Union[bytes, str], path: Union[Path, str]):
         super(TomlConfig, self).__init__()
         self.is_empty_config = False
         self._parse_setting(data)
@@ -23,7 +23,7 @@ def set_key(self, key, value):
         For now only strings are supported.
         We use to update the version number.
         """
-        with open(self.path, "r") as f:
+        with open(self.path, "rb") as f:
             parser = parse(f.read())
 
         parser["tool"]["commitizen"][key] = value
@@ -31,7 +31,7 @@ def set_key(self, key, value):
             f.write(parser.as_string())
         return self
 
-    def _parse_setting(self, data: str):
+    def _parse_setting(self, data: Union[bytes, str]):
         """We expect to have a section in pyproject looking like
 
         ```
diff --git a/commitizen/config/yaml_config.py b/commitizen/config/yaml_config.py
index 510882b9b0..5d199c1929 100644
--- a/commitizen/config/yaml_config.py
+++ b/commitizen/config/yaml_config.py
@@ -7,7 +7,7 @@
 
 
 class YAMLConfig(BaseConfig):
-    def __init__(self, *, data: str, path: Union[Path, str]):
+    def __init__(self, *, data: Union[bytes, str], path: Union[Path, str]):
         super(YAMLConfig, self).__init__()
         self.is_empty_config = False
         self._parse_setting(data)
@@ -17,7 +17,7 @@ def init_empty_config_content(self):
         with open(self.path, "a") as json_file:
             yaml.dump({"commitizen": {}}, json_file)
 
-    def _parse_setting(self, data: str):
+    def _parse_setting(self, data: Union[bytes, str]):
         """We expect to have a section in cz.yaml looking like
 
         ```
@@ -37,7 +37,7 @@ def set_key(self, key, value):
         For now only strings are supported.
         We use to update the version number.
         """
-        with open(self.path, "r") as yaml_file:
+        with open(self.path, "rb") as yaml_file:
             parser = yaml.load(yaml_file, Loader=yaml.FullLoader)
 
         parser["commitizen"][key] = value