diff --git a/jupyterlab_code_formatter/formatters.py b/jupyterlab_code_formatter/formatters.py
index 5c93fe2..ea21f4f 100644
--- a/jupyterlab_code_formatter/formatters.py
+++ b/jupyterlab_code_formatter/formatters.py
@@ -183,9 +183,9 @@ def unescape(self, line: str) -> str:
 def handle_line_ending_and_magic(func):
     @wraps(func)
     def wrapped(self, code: str, notebook: bool, **options) -> str:
-        if any(code.startswith(f"%{lang}") for lang in INCOMPATIBLE_MAGIC_LANGUAGES) or any(
-            code.startswith(f"%%{lang}") for lang in INCOMPATIBLE_MAGIC_LANGUAGES
-        ):
+        if any(
+            code.startswith(f"%{lang}") for lang in INCOMPATIBLE_MAGIC_LANGUAGES
+        ) or any(code.startswith(f"%%{lang}") for lang in INCOMPATIBLE_MAGIC_LANGUAGES):
             logger.info("Non compatible magic language cell block detected, ignoring.")
             return code
 
@@ -382,7 +382,9 @@ def format_code(self, code: str, notebook: bool, **options) -> str:
         from rpy2.robjects import conversion, default_converter
 
         with conversion.localconverter(default_converter):
-            format_r = rpackages.importr(self.package_name, robject_translations={".env": "env"})
+            format_r = rpackages.importr(
+                self.package_name, robject_translations={".env": "env"}
+            )
             formatted_code = format_r.tidy_source(text=code, output=False, **options)
             return "\n".join(formatted_code[0])
 
@@ -398,7 +400,9 @@ def format_code(self, code: str, notebook: bool, **options) -> str:
 
         with conversion.localconverter(default_converter):
             styler_r = rpackages.importr(self.package_name)
-            formatted_code = styler_r.style_text(code, **self._transform_options(styler_r, options))
+            formatted_code = styler_r.style_text(
+                code, **self._transform_options(styler_r, options)
+            )
             return "\n".join(formatted_code)
 
     @staticmethod
@@ -418,13 +422,17 @@ def _transform_options(styler_r, options):
 
         if "reindention" in transformed_options:
             if isinstance(options["reindention"], dict):
-                transformed_options["reindention"] = rpy2.robjects.ListVector(options["reindention"])
+                transformed_options["reindention"] = rpy2.robjects.ListVector(
+                    options["reindention"]
+                )
             else:
                 transformed_options["reindention"] = rpy2.robjects.ListVector(
                     getattr(styler_r, options["reindention"])()
                 )
         return transformed_options
 
+class FormatterError(Exception):
+    pass
 
 class CommandLineFormatter(BaseFormatter):
     command: List[str]
@@ -441,7 +449,9 @@ def importable(self) -> bool:
         return command_exist(self.command[0])
 
     @handle_line_ending_and_magic
-    def format_code(self, code: str, notebook: bool, args: List[str] = [], **options) -> str:
+    def format_code(
+        self, code: str, notebook: bool, args: List[str] = [], **options
+    ) -> str:
         process = subprocess.run(
             self.command + args,
             input=code,
@@ -451,9 +461,14 @@ def format_code(self, code: str, notebook: bool, args: List[str] = [], **options
         )
 
         if process.stderr:
-            logger.info(f"An error with {self.command[0]} has occurred:")
-            logger.info(process.stderr)
-            return code
+            raise FormatterError(
+                f"Error running `{self.command[0]}`:\n" + process.stderr
+            )
+        elif process.returncode != 0:
+            raise FormatterError(
+                f"Formatter `{self.command[0]}` exited with status {process.returncode}"
+                + process.stderr
+            )
         else:
             return process.stdout