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 0792ca1ec..2f9f9007d 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
@@ -299,7 +299,7 @@ $`A=\displaystyle\iint_{S_{\smallsmile}} dA`$<br>
 [EN] This difference in writing is very important. For example in electromagnetism :<br>
 $`\forall S_{\circ}  \oiint_{S_{\smallsmile}} \overrightarrow{B}\cdot\overrightarrow{dA}=0`$, 
 en general $`\iint_{S_{\smallsmile}} \overrightarrow{B}\cdot\overrightarrow{dA}\cancel{=} 0`$
-$`\iint_{S_{\smallsmile}} \overrightarrow{B}\cdot\overrightarrow{dA} != 0`$
+$`\iint_{S_{\smallsmile}} \overrightarrow{B}\cdot\overrightarrow{dA}\not= 0`$