diff --git a/src/calibre/ebooks/rtf/input.py b/src/calibre/ebooks/rtf/input.py
index 75c839eb83..57903a6711 100644
--- a/src/calibre/ebooks/rtf/input.py
+++ b/src/calibre/ebooks/rtf/input.py
@@ -292,7 +292,8 @@ class RTFInput(InputFormatPlugin):
# Replace newlines inserted by the 'empty_paragraphs' option in rtf2xml with html blank lines
if not getattr(self.options, 'remove_paragraph_spacing', False):
res = re.sub('\s*', '', res)
- res = re.sub('(?<=\n)\n{2}', u'\u00a0
\n', res)
+ res = re.sub('(?<=\n)\n{2}',
+ u'\u00a0
\n'.encode('utf-8'), res)
if self.options.preprocess_html:
preprocessor = PreProcessor(self.options, log=getattr(self, 'log', None))
res = preprocessor(res)