diff --git a/climada/entity/exposures/base.py b/climada/entity/exposures/base.py
index c7e25604e..fec6499ae 100644
--- a/climada/entity/exposures/base.py
+++ b/climada/entity/exposures/base.py
@@ -996,7 +996,9 @@ def concat(exposures_list):
         ]
         crss = [
             ex.crs for ex in exposures_list
-            if isinstance(ex, (Exposures, GeoDataFrame)) and not ex.crs is None
+            if isinstance(ex, (Exposures, GeoDataFrame))
+            and hasattr(ex, "crs")
+            and ex.crs is not None
         ]
         if crss:
             crs = crss[0]
diff --git a/climada/entity/exposures/test/test_base.py b/climada/entity/exposures/test/test_base.py
index cad29cee7..c321ca08f 100644
--- a/climada/entity/exposures/test/test_base.py
+++ b/climada/entity/exposures/test/test_base.py
@@ -447,7 +447,7 @@ def test_set_gdf(self):
         probe.set_gdf(empty_gdf)
         self.assertTrue(probe.gdf.equals(gpd.GeoDataFrame()))
         self.assertTrue(u_coord.equal_crs(DEF_CRS, probe.crs))
-        self.assertIsNone(probe.gdf.crs)
+        self.assertFalse(hasattr(probe.gdf, "crs"))
 
         probe.set_gdf(gdf_with_geometry)
         self.assertTrue(probe.gdf.equals(gdf_with_geometry))
@@ -457,7 +457,7 @@ def test_set_gdf(self):
         probe.set_gdf(gdf_without_geometry)
         self.assertTrue(probe.gdf.equals(good_exposures().gdf))
         self.assertTrue(u_coord.equal_crs(DEF_CRS, probe.crs))
-        self.assertIsNone(probe.gdf.crs)
+        self.assertFalse(hasattr(probe.gdf, "crs"))
 
     def test_set_crs(self):
         """Test setting the CRS"""
diff --git a/climada/entity/measures/test/test_base.py b/climada/entity/measures/test/test_base.py
index 62ff2f31e..3fc7e8a98 100644
--- a/climada/entity/measures/test/test_base.py
+++ b/climada/entity/measures/test/test_base.py
@@ -280,7 +280,8 @@ def test_filter_exposures_pass(self):
         self.assertEqual(res_exp.tag.file_name, exp.tag.file_name)
         self.assertEqual(res_exp.tag.description, exp.tag.description)
         self.assertTrue(u_coord.equal_crs(res_exp.crs, exp.crs))
-        self.assertTrue(u_coord.equal_crs(res_exp.gdf.crs, exp.gdf.crs))
+        self.assertFalse(hasattr(exp.gdf, "crs"))
+        self.assertFalse(hasattr(res_exp.gdf, "crs"))
 
         # regions (that is just input data, no need for testing, but it makes the changed and unchanged parts obious)
         self.assertTrue(np.array_equal(res_exp.gdf.region_id.values[0], 4))
diff --git a/climada/util/test/test_coordinates.py b/climada/util/test/test_coordinates.py
index 60400befa..71292ac31 100644
--- a/climada/util/test/test_coordinates.py
+++ b/climada/util/test/test_coordinates.py
@@ -1191,7 +1191,7 @@ def test_points_to_raster_pass(self):
         df_val['value'] = np.ones(len(df_val)) * 10
         crs = 'epsg:2202'
         _raster, meta = u_coord.points_to_raster(df_val, val_names=['value'], crs=crs)
-        self.assertIsNone(df_val.crs)  # points_to_raster must not modify df_val
+        self.assertFalse(hasattr(df_val, "crs"))  # points_to_raster must not modify df_val
         self.assertTrue(u_coord.equal_crs(meta['crs'], crs))
         self.assertAlmostEqual(meta['transform'][0], 0.5)
         self.assertAlmostEqual(meta['transform'][1], 0)