diff --git a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/42.relativistic-mechanics/10.n1/20.overview/cheatsheet.fr.md b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/42.relativistic-mechanics/10.n1/20.overview/cheatsheet.fr.md
index 9804075d1..357ae42f9 100644
--- a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/42.relativistic-mechanics/10.n1/20.overview/cheatsheet.fr.md
+++ b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/42.relativistic-mechanics/10.n1/20.overview/cheatsheet.fr.md
@@ -73,3 +73,8 @@ Référentiel femme :
 ![](cadre-special-relativity-physics-Lorentz-transformation-Ref2-1_L1200.gif)
 
 transformation de Lorentz
+
+Domaine de validité
+
+![](special-relativity-domain-validity_EN_L1200.gif)    
+version anglaise, pour test lisibilité
\ No newline at end of file