diff --git a/poincare/src/n_ary_expression.cpp b/poincare/src/n_ary_expression.cpp
index 538c1f21b..8cd1283b1 100644
--- a/poincare/src/n_ary_expression.cpp
+++ b/poincare/src/n_ary_expression.cpp
@@ -32,7 +32,12 @@ void NAryExpressionNode::sortChildrenInPlace(ExpressionOrder order, Context * co
        * multiplication) so we never swap 2 matrices. */
       ExpressionNode * cj = childAtIndex(j);
       ExpressionNode * cj1 = childAtIndex(j+1);
-      if (order(cj, cj1, canBeInterrupted) > 0 && (canSwapMatrices || !(Expression(cj).deepIsMatrix(context) && Expression(cj1).deepIsMatrix(context)))) {
+      bool cjIsMatrix = Expression(cj).deepIsMatrix(context);
+      bool cj1IsMatrix = Expression(cj1).deepIsMatrix(context);
+      bool cj1GreaterThanCj = order(cj, cj1, canBeInterrupted) > 0;
+      if ((cjIsMatrix && !cj1IsMatrix) || // we always put matrices at the end of expressions
+          (cjIsMatrix && cj1IsMatrix && canSwapMatrices && cj1GreaterThanCj) ||
+          (!cjIsMatrix && !cj1IsMatrix && cj1GreaterThanCj)) {
         reference.swapChildrenInPlace(j, j+1);
         isSorted = false;
       }
diff --git a/poincare/test/expression_order.cpp b/poincare/test/expression_order.cpp
index 57739d145..59ec0dc6c 100644
--- a/poincare/test/expression_order.cpp
+++ b/poincare/test/expression_order.cpp
@@ -216,4 +216,14 @@ QUIZ_CASE(poincare_expression_order_addition_multiplication) {
     assert_multiplication_or_addition_is_ordered_as(e1, e2);
   }
 
+  {
+    // ∑Matrix + 𝐢  -> 𝐢 + ∑Matrix
+    Expression childMatrix = Matrix::Builder();
+    static_cast<Matrix &>(childMatrix).addChildAtIndexInPlace(Rational::Builder(0), 0, 0);
+    Expression child1 = Sum::Builder(childMatrix, Symbol::Builder('n'), Rational::Builder(0), Rational::Builder(0));
+    Expression child2 = Symbol::Builder(UCodePointMathematicalBoldSmallI);
+    Expression e1 = Addition::Builder(child1.clone(), child2.clone());
+    Expression e2 = Addition::Builder(child2, child1);
+    assert_multiplication_or_addition_is_ordered_as(e1, e2);
+  }
 }