diff --git a/hdr.tex b/hdr.tex
index 4708d77..c2ea7cc 100644
--- a/hdr.tex
+++ b/hdr.tex
@@ -5,7 +5,7 @@
 %%%% manuscrit de HDR.
 %%%% 5 janvier 2024
 
-\documentclass[english,12pt,a4paper]{book}
+\documentclass[12pt,a4paper]{book}
 \usepackage{amsmath}
 \usepackage{amsfonts}
 \usepackage{fancyhdr}
@@ -24,10 +24,14 @@
 \usepackage{hyperref}
 \usepackage[language=english]{lipsum}
 \usepackage{fontspec}
+\usepackage{polyglossia}
 
 \setmainfont{Linux Libertine O}
 \setsansfont{Linux Biolinum O}
 
+\setdefaultlanguage{english}
+\setotherlanguages{french}
+
 \graphicspath{{pics/}}
 \usetikzlibrary{calc}