diff --git a/doc/frama-c-book.cls b/doc/frama-c-book.cls
index 6e54587fc9b467d21e380b369722b1f0c9ca0d64..8587442f5f54d201baabd96f941bcb37dab5fce5 100644
--- a/doc/frama-c-book.cls
+++ b/doc/frama-c-book.cls
@@ -410,7 +410,7 @@
 
 \newcommand{\lstbrk}{\mbox{$\color{blue}\scriptstyle\cdots$}}
 
-\def\lp@basic{\ifmmode\normalfont\mathtt\mdseries\small\else\normalfont\ttfamily\mdseries\normalsize\fi}
+\def\lp@basic{\ifmmode\normalfont\mathtt\mdseries\small\else\normalfont\ttfamily\mdseries\small\fi}
 \def\lp@inline{\ifmmode\normalfont\mathtt\scriptstyle\else\normalfont\ttfamily\mdseries\normalsize\fi}
 \def\lp@keyword{}
 \def\lp@special{\color{frama-c-dark-orange}}