diff --git a/django/test/signals.py b/django/test/signals.py
index 371b90c9ee..6f6d5aec81 100644
--- a/django/test/signals.py
+++ b/django/test/signals.py
@@ -10,6 +10,7 @@ from django.db import connections, router
 from django.db.utils import ConnectionRouter
 from django.dispatch import Signal, receiver
 from django.utils import six, timezone
+from django.utils.formats import FORMAT_SETTINGS, reset_format_cache
 from django.utils.functional import empty
 
 template_rendered = Signal(providing_args=["template", "context"])
@@ -117,6 +118,12 @@ def language_changed(**kwargs):
         trans_real.check_for_language.cache_clear()
 
 
+@receiver(setting_changed)
+def localize_settings_changed(**kwargs):
+    if kwargs['setting'] in FORMAT_SETTINGS or kwargs['setting'] == 'USE_THOUSAND_SEPARATOR':
+        reset_format_cache()
+
+
 @receiver(setting_changed)
 def file_storage_changed(**kwargs):
     if kwargs['setting'] == 'DEFAULT_FILE_STORAGE':
diff --git a/tests/admin_views/tests.py b/tests/admin_views/tests.py
index b65439f8ac..2d86487e51 100644
--- a/tests/admin_views/tests.py
+++ b/tests/admin_views/tests.py
@@ -186,9 +186,6 @@ class AdminViewBasicTestCase(TestCase):
     def setUp(self):
         self.client.force_login(self.superuser)
 
-    def tearDown(self):
-        formats.reset_format_cache()
-
     def assertContentBefore(self, response, text1, text2, failing_msg=None):
         """
         Testing utility asserting that text1 appears before text2 in response
@@ -5301,9 +5298,6 @@ class DateHierarchyTests(TestCase):
     def setUp(self):
         self.client.force_login(self.superuser)
 
-    def tearDown(self):
-        formats.reset_format_cache()
-
     def assert_non_localized_year(self, response, year):
         """
         The year is not localized with USE_THOUSAND_SEPARATOR (#15234).
diff --git a/tests/i18n/tests.py b/tests/i18n/tests.py
index fdd8903e0f..ed267ef1d6 100644
--- a/tests/i18n/tests.py
+++ b/tests/i18n/tests.py
@@ -731,17 +731,16 @@ class FormattingTests(SimpleTestCase):
         even if they would be interpreted as False in a conditional test
         (e.g. 0 or empty string) (#16938).
         """
-        with patch_formats('fr', THOUSAND_SEPARATOR='', FIRST_DAY_OF_WEEK=0):
-            with translation.override('fr'):
-                with self.settings(USE_THOUSAND_SEPARATOR=True, THOUSAND_SEPARATOR='!'):
-                    self.assertEqual('', get_format('THOUSAND_SEPARATOR'))
-                    # Even a second time (after the format has been cached)...
-                    self.assertEqual('', get_format('THOUSAND_SEPARATOR'))
+        with translation.override('fr'):
+            with self.settings(USE_THOUSAND_SEPARATOR=True, THOUSAND_SEPARATOR='!'):
+                self.assertEqual('\xa0', get_format('THOUSAND_SEPARATOR'))
+                # Even a second time (after the format has been cached)...
+                self.assertEqual('\xa0', get_format('THOUSAND_SEPARATOR'))
 
-                with self.settings(FIRST_DAY_OF_WEEK=1):
-                    self.assertEqual(0, get_format('FIRST_DAY_OF_WEEK'))
-                    # Even a second time (after the format has been cached)...
-                    self.assertEqual(0, get_format('FIRST_DAY_OF_WEEK'))
+            with self.settings(FIRST_DAY_OF_WEEK=0):
+                self.assertEqual(1, get_format('FIRST_DAY_OF_WEEK'))
+                # Even a second time (after the format has been cached)...
+                self.assertEqual(1, get_format('FIRST_DAY_OF_WEEK'))
 
     def test_l10n_enabled(self):
         self.maxDiff = 3000
@@ -1161,8 +1160,8 @@ class FormattingTests(SimpleTestCase):
             with self.settings(USE_THOUSAND_SEPARATOR=True, USE_L10N=False):
                 self.assertEqual(sanitize_separators('12\xa0345'), '12\xa0345')
 
-        with patch_formats(get_language(), THOUSAND_SEPARATOR='.', DECIMAL_SEPARATOR=','):
-            with self.settings(USE_THOUSAND_SEPARATOR=True):
+        with self.settings(USE_THOUSAND_SEPARATOR=True):
+            with patch_formats(get_language(), THOUSAND_SEPARATOR='.', DECIMAL_SEPARATOR=','):
                 self.assertEqual(sanitize_separators('10.234'), '10234')
                 # Suspicion that user entered dot as decimal separator (#22171)
                 self.assertEqual(sanitize_separators('10.10'), '10.10')