diff --git a/src/flake8/options/config.py b/src/flake8/options/config.py
index 9325495..9054315 100644
--- a/src/flake8/options/config.py
+++ b/src/flake8/options/config.py
@@ -69,6 +69,9 @@ class ConfigFileFinder(object):
         found_files = []
         for filename in files:
             try:
+                if sys.version_info < (3,) and isinstance(filename, bytes):
+                    filename = filename.decode('UTF-8')
+
                 found_files.extend(config.read(filename))
             except UnicodeDecodeError:
                 LOG.exception(