diff --git a/interfaces/cython/cantera/composite.pyx b/interfaces/cython/cantera/composite.pyx
index c111726e5..140f52ab9 100644
--- a/interfaces/cython/cantera/composite.pyx
+++ b/interfaces/cython/cantera/composite.pyx
@@ -1,4 +1,5 @@
 class Solution(ThermoPhase, Kinetics, Transport):
+    __slots__ = ()
     """
     A class for chemically-reacting solutions.
 
@@ -13,6 +14,7 @@ class Solution(ThermoPhase, Kinetics, Transport):
     """
 
 class Interface(InterfacePhase, InterfaceKinetics):
+    __slots__ = ('_phase_indices',)
     """
     Two-dimensional interfaces.
 
@@ -23,6 +25,7 @@ class Interface(InterfacePhase, InterfaceKinetics):
     """
 
 class DustyGas(ThermoPhase, Kinetics, DustyGasTransport):
+    __slots__ = ()
     """
     A composite class which models a gas in a stationary, solid, porous medium.
 
diff --git a/interfaces/cython/cantera/onedim.py b/interfaces/cython/cantera/onedim.py
index df81c79ee..4dc13ea2b 100644
--- a/interfaces/cython/cantera/onedim.py
+++ b/interfaces/cython/cantera/onedim.py
@@ -10,6 +10,7 @@ except ImportError:
 
 class FlameBase(Sim1D):
     """ Base class for flames with a single flow domain """
+    __slots__ = ('gas',)
 
     def __init__(self, domains, gas, grid=None):
         """
@@ -223,6 +224,7 @@ for attr in ['forward_rates_of_progress', 'reverse_rates_of_progress', 'net_rate
 
 class FreeFlame(FlameBase):
     """A freely-propagating flat flame."""
+    __slots__ = ('inlet', 'outlet', 'flame')
 
     def __init__(self, gas, grid=None):
         """
@@ -268,6 +270,7 @@ class FreeFlame(FlameBase):
 
 class BurnerFlame(FlameBase):
     """A burner-stabilized flat flame."""
+    __slots__ = ('burner', 'flame', 'outlet')
 
     def __init__(self, gas, grid=None):
         """
@@ -321,6 +324,7 @@ class BurnerFlame(FlameBase):
 
 class CounterflowDiffusionFlame(FlameBase):
     """ A counterflow diffusion flame """
+    __slots__ = ('fuel_inlet', 'flame', 'oxidizer_inlet')
 
     def __init__(self, gas, grid=None):
         """
@@ -434,6 +438,8 @@ class CounterflowDiffusionFlame(FlameBase):
 
 class ImpingingJet(FlameBase):
     """An axisymmetric flow impinging on a surface at normal incidence."""
+    __slots__ = ('inlet', 'flame', 'surface')
+
     def __init__(self, gas, grid=None, surface=None):
         """
         :param gas:
@@ -500,6 +506,7 @@ class ImpingingJet(FlameBase):
 
 class CounterflowPremixedFlame(FlameBase):
     """ A premixed counterflow flame """
+    __slots__ = ('reactants', 'flame', 'products')
 
     def __init__(self, gas, grid=None):
         """
diff --git a/interfaces/cython/cantera/test/test_mixture.py b/interfaces/cython/cantera/test/test_mixture.py
index 7ee1f2c2a..7dd69f73d 100644
--- a/interfaces/cython/cantera/test/test_mixture.py
+++ b/interfaces/cython/cantera/test/test_mixture.py
@@ -180,3 +180,10 @@ class TestMixture(utilities.CanteraTest):
         self.assertArrayNear(E1, E2)
         self.assertNear(self.mix.T, 400)
         self.assertNear(self.mix.P, 2 * ct.one_atm)
+
+    def test_invalid_property(self):
+        x = self.mix
+        with self.assertRaises(AttributeError):
+            x.foobar = 300
+        with self.assertRaises(AttributeError):
+            x.foobar
diff --git a/interfaces/cython/cantera/test/test_onedim.py b/interfaces/cython/cantera/test/test_onedim.py
index 3c784816e..3ed41e994 100644
--- a/interfaces/cython/cantera/test/test_onedim.py
+++ b/interfaces/cython/cantera/test/test_onedim.py
@@ -74,6 +74,18 @@ class TestOnedim(utilities.CanteraTest):
         with self.assertRaises(NotImplementedError):
             copy.copy(flame)
 
+    def test_invalid_property(self):
+        gas1 = ct.Solution('h2o2.xml')
+        inlet = ct.Inlet1D(name='something', phase=gas1)
+        flame = ct.FreeFlow(gas1)
+        sim = ct.Sim1D((inlet, flame))
+
+        for x in (inlet, flame, sim):
+            with self.assertRaises(AttributeError):
+                x.foobar = 300
+            with self.assertRaises(AttributeError):
+                x.foobar
+
 
 class TestFreeFlame(utilities.CanteraTest):
     tol_ss = [1.0e-5, 1.0e-14]  # [rtol atol] for steady-state problem
diff --git a/interfaces/cython/cantera/test/test_reactor.py b/interfaces/cython/cantera/test/test_reactor.py
index 86b7b2c7c..c9d323685 100644
--- a/interfaces/cython/cantera/test/test_reactor.py
+++ b/interfaces/cython/cantera/test/test_reactor.py
@@ -512,6 +512,14 @@ class TestReactor(utilities.CanteraTest):
         with self.assertRaises(NotImplementedError):
             copy.copy(self.net)
 
+    def test_invalid_property(self):
+        self.make_reactors()
+        for x in (self.r1, self.net):
+            with self.assertRaises(AttributeError):
+                x.foobar = 300
+            with self.assertRaises(AttributeError):
+                x.foobar
+
 
 class TestIdealGasReactor(TestReactor):
     reactorClass = ct.IdealGasReactor
diff --git a/interfaces/cython/cantera/test/test_thermo.py b/interfaces/cython/cantera/test/test_thermo.py
index bb207cb78..3c12e8a69 100644
--- a/interfaces/cython/cantera/test/test_thermo.py
+++ b/interfaces/cython/cantera/test/test_thermo.py
@@ -8,7 +8,7 @@ class TestThermoPhase(utilities.CanteraTest):
     def setUp(self):
         self.phase = ct.Solution('h2o2.xml')
 
-    def teste_phases(self):
+    def test_phases(self):
         self.assertEqual(self.phase.n_phases, 1)
 
     def test_species(self):
@@ -308,6 +308,13 @@ class TestThermoPhase(utilities.CanteraTest):
         with self.assertRaises(AssertionError):
             self.phase.UVX = -4e5, 4.4, 'H2:1.0', -1
 
+    def test_invalid_property(self):
+        x = self.phase
+        with self.assertRaises(AttributeError):
+            x.foobar = 300
+        with self.assertRaises(AttributeError):
+            x.foobar
+
     def check_getters(self):
         T,P,X = self.phase.TPX
         self.assertNear(T, self.phase.T)