diff --git a/pypowsybl/network/impl/perunit.py b/pypowsybl/network/impl/perunit.py
index 8b20aefb4..f9af72744 100644
--- a/pypowsybl/network/impl/perunit.py
+++ b/pypowsybl/network/impl/perunit.py
@@ -48,7 +48,7 @@ def sn(self) -> float:
         """
         The base power, in MW, used for per-uniting
         """
-        return self._network.nominal_apparent_power()
+        return self._network.nominal_apparent_power
 
     def get_buses(self) -> pd.DataFrame:
         return self._network.get_buses()
diff --git a/tests/test_per_unit.py b/tests/test_per_unit.py
index c08685b33..ab2f6d71f 100644
--- a/tests/test_per_unit.py
+++ b/tests/test_per_unit.py
@@ -18,6 +18,7 @@ def test_bus_per_unit():
     pp.loadflow.run_ac(n)
     with pytest.warns(DeprecationWarning, match=re.escape("Per-unit view is deprecated and slow (make a deep copy of the network), use per unit mode of the network instead")):
         n = per_unit_view(n, 100)
+    assert n.sn == 100.0
     buses = n.get_buses()
     expected = pd.DataFrame(index=pd.Series(name='id', data=['VLGEN_0', 'VLHV1_0', 'VLHV2_0', 'VLLOAD_0']),
                             columns=['name', 'v_mag', 'v_angle', 'connected_component', 'synchronous_component',