diff --git a/concrete/numpy/tracing.py b/concrete/numpy/tracing.py
index 32dd4f9ab..727ed6e47 100644
--- a/concrete/numpy/tracing.py
+++ b/concrete/numpy/tracing.py
@@ -661,11 +661,9 @@ def _on_numpy_matmul(lhs: NPTracer, rhs: NPTracer):
             rhs = rhs.reshape((rhs_output.shape[0], 1))
         elif lhs_output.ndim == 1:
             # lhs is a vector, reshape to be 2D and give proper result
-            output_shape = lhs_output.shape
             lhs = lhs.reshape((1, lhs_output.shape[0]))
         elif rhs_output.ndim == 1:
             # rhs is a vector, reshape to be 2D and give proper result
-            output_shape = rhs_output.shape
             rhs = rhs.reshape((rhs_output.shape[0], 1))
 
     traced_computation = MatMul(
diff --git a/tests/numpy/test_compile.py b/tests/numpy/test_compile.py
index ed23f208e..f32f5f205 100644
--- a/tests/numpy/test_compile.py
+++ b/tests/numpy/test_compile.py
@@ -1359,6 +1359,16 @@ def test_compile_and_run_constant_dot_correctness(
             (2, 3),
             (-4, 3),
         ),
+        pytest.param(
+            (5,),
+            (5, 3),
+            (0, 4),
+        ),
+        pytest.param(
+            (5, 3),
+            (3,),
+            (0, 4),
+        ),
     ],
 )
 def test_compile_and_run_matmul_correctness(