diff --git a/test/test_cache.py b/test/test_cache.py
index 7ef490e..286aba8 100644
--- a/test/test_cache.py
+++ b/test/test_cache.py
@@ -60,6 +60,42 @@ def test_cache():
     assert 'u2' in settings._p_.get_cached()
 
 
+def test_cache_importation():
+    od1 = make_description()
+    api = getapi(Config(od1))
+    api.option('u2').value.set(1)
+    export = api.value.exportation()
+    assert api.option.make_dict() == {'u1': [], 'u2': 1, 'u3': []}
+    api.option('u2').value.set(2)
+    assert api.option.make_dict() == {'u1': [], 'u2': 2, 'u3': []}
+    api.value.importation(export)
+    assert api.option.make_dict() == {'u1': [], 'u2': 1, 'u3': []}
+
+
+def test_cache_importation_property():
+    od1 = make_description()
+    api = getapi(Config(od1))
+    api.option('u2').property.add('prop')
+    export = api.property.exportation()
+    assert api.option('u2').property.get() == {'prop'}
+    api.option('u2').property.add('prop2')
+    assert api.option('u2').property.get() == {'prop', 'prop2'}
+    api.property.importation(export)
+    assert api.option('u2').property.get() == {'prop'}
+
+
+def test_cache_importation_permissive():
+    od1 = make_description()
+    api = getapi(Config(od1))
+    api.option('u2').permissive.set(frozenset(['prop']))
+    export = api.permissive.exportation()
+    assert api.option('u2').permissive.get() == {'prop'}
+    api.option('u2').permissive.set(frozenset(['prop', 'prop2']))
+    assert api.option('u2').permissive.get() == {'prop', 'prop2'}
+    api.permissive.importation(export)
+    assert api.option('u2').permissive.get() == {'prop'}
+
+
 #def test_get_cache():
 #    # force a value in cache, try if reget corrupted value
 #    od1 = make_description()
diff --git a/tiramisu/api.py b/tiramisu/api.py
index bc4c0ac..1ca9718 100644
--- a/tiramisu/api.py
+++ b/tiramisu/api.py
@@ -773,7 +773,8 @@ class TiramisuContextValue(TiramisuContext):
     @count
     def importation(self, values):
         """import values"""
-        return self.config_bag.config.cfgimpl_get_values()._p_.importation(values)
+        self.config_bag.config.cfgimpl_get_values()._p_.importation(values)
+        self.config_bag.config.cfgimpl_reset_cache(None, None, None)
 
 
 class TiramisuContextOwner(TiramisuContext):
@@ -855,7 +856,8 @@ class TiramisuContextProperty(TiramisuContext):
     @count
     def importation(self, properties):
         """import configuration properties"""
-        return self.config_bag.config.cfgimpl_get_settings()._p_.importation(properties)
+        self.config_bag.config.cfgimpl_get_settings()._p_.importation(properties)
+        self.config_bag.config.cfgimpl_reset_cache(None, None, None)
 
 
 class TiramisuContextPermissive(TiramisuContext):
@@ -880,6 +882,7 @@ class TiramisuContextPermissive(TiramisuContext):
     def importation(self, permissives):
         """import configuration permissives"""
         self.config_bag.config.cfgimpl_get_settings()._pp_.importation(permissives)
+        self.config_bag.config.cfgimpl_reset_cache(None, None, None)