diff --git a/hgext/convert/gnuarch.py b/hgext/convert/gnuarch.py
--- a/hgext/convert/gnuarch.py
+++ b/hgext/convert/gnuarch.py
@@ -298,26 +298,26 @@
 
     def _parsecatlog(self, data, rev):
         try:
-            catlog = self.catlogparser.parsestr(data)
+            catlog = self.catlogparser.parsestr(encoding.unifromlocal(data))
 
             # Commit date
             self.changes[rev].date = dateutil.datestr(
-                dateutil.strdate(catlog[b'Standard-date'], b'%Y-%m-%d %H:%M:%S')
+                dateutil.strdate(catlog['Standard-date'], b'%Y-%m-%d %H:%M:%S')
             )
 
             # Commit author
-            self.changes[rev].author = self.recode(catlog[b'Creator'])
+            self.changes[rev].author = self.recode(catlog['Creator'])
 
             # Commit description
-            self.changes[rev].summary = b'\n\n'.join(
-                (catlog[b'Summary'], catlog.get_payload())
+            self.changes[rev].summary = '\n\n'.join(
+                (catlog['Summary'], catlog.get_payload())
             )
             self.changes[rev].summary = self.recode(self.changes[rev].summary)
 
             # Commit revision origin when dealing with a branch or tag
-            if b'Continuation-of' in catlog:
+            if 'Continuation-of' in catlog:
                 self.changes[rev].continuationof = self.recode(
-                    catlog[b'Continuation-of']
+                    catlog['Continuation-of']
                 )
         except Exception:
             raise error.Abort(_(b'could not parse cat-log of %s') % rev)