diff --git a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
index 5c083bcdc..2f70d9a14 100644
--- a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
+++ b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
@@ -225,7 +225,7 @@ In Cartesian coordinates, the base vectors keep the
**same direction whatever the position of the point $`M`$**.
$`(\overrightarrow{e_x},\overrightarrow{e_y},\overrightarrow{e_z})`$
base ortogonal independiente de la posición de $`M`$ / base orthogonale indépendante
-de la position de $`M`$ / orthogonal basis independent of the position of $`M`$.
+de la position de $`M`$ / orthogonal basis independent of the position of $`M`$.
$`||\overrightarrow{e_x}||=||\overrightarrow{e_y}||=||\overrightarrow{e_z}||=1`$
$`\overrightarrow{e_x}\perp\overrightarrow{e_y}\quad,\quad\overrightarrow{e_y}
\perp\overrightarrow{e_z}\quad,\quad\overrightarrow{e_x}\perp\overrightarrow{e_z}`$