diff --git a/ci/authors-rst.py b/ci/authors-rst.py
index b9ef48d7c..6f3717276 100755
--- a/ci/authors-rst.py
+++ b/ci/authors-rst.py
@@ -35,6 +35,8 @@ def main():
                     error(line_number, 'bad table divider')
                 if line != lines[first_div_index]:
                     error(line_number, 'malformed table divider')
+            if line == lines[first_div_index + i - 1]:
+                error(line_number, 'duplicate of previous line')
         if len(div_indices) < 3:
             error(len(lines), 'missing table divider(s)')
         for i in div_indices[3:]:
diff --git a/docs/about/Authors.rst b/docs/about/Authors.rst
index 7c299b995..07909b15c 100644
--- a/docs/about/Authors.rst
+++ b/docs/about/Authors.rst
@@ -156,7 +156,6 @@ Peter Hansen            previsualconsent
 Petr Mrázek             peterix
 Pfhreak                 Pfhreak
 Pierre Lulé             plule
-Pierre Lulé             plule
 Pierre-David Bélanger   pierredavidbelanger
 potato
 ppaawwll                ppaawwll                🐇🐇🐇🐇