diff --git a/manila/tests/test_utils.py b/manila/tests/test_utils.py
index 9fdf051084..c8bc59146c 100644
--- a/manila/tests/test_utils.py
+++ b/manila/tests/test_utils.py
@@ -114,19 +114,25 @@ class GenericUtilsTestCase(test.TestCase):
     @ddt.data(
         (("3G", "G"), 3.0),
         (("4.1G", "G"), 4.1),
+        (("4,1G", "G"), 4.1),
         (("5.23G", "G"), 5.23),
+        (("5,23G", "G"), 5.23),
         (("9728M", "G"), 9.5),
         (("8192K", "G"), 0.0078125),
         (("2T", "G"), 2048.0),
         (("2.1T", "G"), 2150.4),
+        (("2,1T", "G"), 2150.4),
         (("3P", "G"), 3145728.0),
         (("3.4P", "G"), 3565158.4),
+        (("3,4P", "G"), 3565158.4),
         (("9728M", "M"), 9728.0),
         (("9728.2381T", "T"), 9728.2381),
+        (("9728,2381T", "T"), 9728.2381),
         (("0", "G"), 0.0),
         (("512", "M"), 0.00048828125),
         (("2097152.", "M"), 2.0),
         ((".1024", "K"), 0.0001),
+        ((",1024", "K"), 0.0001),
         (("2048G", "T"), 2.0),
         (("65536G", "P"), 0.0625),
     )
@@ -143,6 +149,14 @@ class GenericUtilsTestCase(test.TestCase):
         ("1KM", "G"),
         ("K1M", "G"),
         ("M1K", "G"),
+        ("1.2fake", "G"),
+        ("1,2fake", "G"),
+        ("2.2GG", "G"),
+        ("1.1KM", "G"),
+        ("K2.2M", "G"),
+        ("K2,2M", "G"),
+        ("M2.2K", "G"),
+        ("M2,2K", "G"),
         ("", "G"),
         (23, "G"),
         (23.0, "G"),
diff --git a/manila/utils.py b/manila/utils.py
index 16720502cd..7325d3bf10 100644
--- a/manila/utils.py
+++ b/manila/utils.py
@@ -550,14 +550,15 @@ def translate_string_size_to_float(string, multiplier='G'):
             }
         )
     try:
-        value = float(string) / 1024.0
+        value = float(string.replace(",", ".")) / 1024.0
         value = value / mapping[multiplier]
         return value
     except (ValueError, TypeError):
         matched = re.match(
-            r"^(\d+\.*\d*)([%s])$" % ','.join(multipliers), string)
+            r"^(\d*[.,]*\d*)([%s])$" % ''.join(multipliers), string)
         if matched:
-            value = float(matched.groups()[0])
+            # The replace() is needed in case decimal separator is a comma
+            value = float(matched.groups()[0].replace(",", "."))
             multiplier = mapping[matched.groups()[1]] / mapping[multiplier]
             return value * multiplier
 
diff --git a/releasenotes/notes/bug-1714691-decimal-separators-in-locales-392c0c794c49c1c2.yaml b/releasenotes/notes/bug-1714691-decimal-separators-in-locales-392c0c794c49c1c2.yaml
new file mode 100644
index 0000000000..13bc8fd4b5
--- /dev/null
+++ b/releasenotes/notes/bug-1714691-decimal-separators-in-locales-392c0c794c49c1c2.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+  - Fixed issue where locales other than POSIX and en_US.UTF-8 might
+    cause the translate_string_size_to_float method to fail on a
+    comma decimal separator instead of a period decimal separator.