diff --git a/src/Symfony/Component/Form/Extension/Core/DataTransformer/IntegerToLocalizedStringTransformer.php b/src/Symfony/Component/Form/Extension/Core/DataTransformer/IntegerToLocalizedStringTransformer.php
index 51c3821f9e29..ca69b5fe8a8b 100644
--- a/src/Symfony/Component/Form/Extension/Core/DataTransformer/IntegerToLocalizedStringTransformer.php
+++ b/src/Symfony/Component/Form/Extension/Core/DataTransformer/IntegerToLocalizedStringTransformer.php
@@ -11,6 +11,8 @@
 
 namespace Symfony\Component\Form\Extension\Core\DataTransformer;
 
+use Symfony\Component\Form\Exception\TransformationFailedException;
+
 /**
  * Transforms between an integer and a localized number with grouping
  * (each thousand) and comma separators.
@@ -40,6 +42,12 @@ public function __construct($scale = 0, $grouping = false, $roundingMode = self:
      */
     public function reverseTransform($value)
     {
+        $decimalSeparator = $this->getNumberFormatter()->getSymbol(\NumberFormatter::DECIMAL_SEPARATOR_SYMBOL);
+
+        if (\is_string($value) && false !== strpos($value, $decimalSeparator)) {
+            throw new TransformationFailedException(sprintf('The value "%s" is not a valid integer.', $value));
+        }
+
         $result = parent::reverseTransform($value);
 
         return null !== $result ? (int) $result : null;
diff --git a/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/IntegerToLocalizedStringTransformerTest.php b/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/IntegerToLocalizedStringTransformerTest.php
index 193aba91ab3b..8cdbb1959a79 100644
--- a/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/IntegerToLocalizedStringTransformerTest.php
+++ b/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/IntegerToLocalizedStringTransformerTest.php
@@ -95,9 +95,7 @@ public function testReverseTransform()
         $transformer = new IntegerToLocalizedStringTransformer();
 
         $this->assertEquals(1, $transformer->reverseTransform('1'));
-        $this->assertEquals(1, $transformer->reverseTransform('1,5'));
-        $this->assertEquals(1234, $transformer->reverseTransform('1234,5'));
-        $this->assertEquals(12345, $transformer->reverseTransform('12345,912'));
+        $this->assertEquals(12345, $transformer->reverseTransform('12345'));
     }
 
     public function testReverseTransformEmpty()
@@ -116,10 +114,10 @@ public function testReverseTransformWithGrouping()
 
         $transformer = new IntegerToLocalizedStringTransformer(null, true);
 
-        $this->assertEquals(1234, $transformer->reverseTransform('1.234,5'));
-        $this->assertEquals(12345, $transformer->reverseTransform('12.345,912'));
-        $this->assertEquals(1234, $transformer->reverseTransform('1234,5'));
-        $this->assertEquals(12345, $transformer->reverseTransform('12345,912'));
+        $this->assertEquals(1234, $transformer->reverseTransform('1.234'));
+        $this->assertEquals(12345, $transformer->reverseTransform('12.345'));
+        $this->assertEquals(1234, $transformer->reverseTransform('1234'));
+        $this->assertEquals(12345, $transformer->reverseTransform('12345'));
     }
 
     public function reverseTransformWithRoundingProvider()
@@ -203,6 +201,29 @@ public function testReverseTransformExpectsValidNumber()
         $transformer->reverseTransform('foo');
     }
 
+    /**
+     * @dataProvider floatNumberProvider
+     * @expectedException \Symfony\Component\Form\Exception\TransformationFailedException
+     */
+    public function testReverseTransformExpectsInteger($number, $locale)
+    {
+        IntlTestHelper::requireFullIntl($this, false);
+
+        \Locale::setDefault($locale);
+
+        $transformer = new IntegerToLocalizedStringTransformer();
+
+        $transformer->reverseTransform($number);
+    }
+
+    public function floatNumberProvider()
+    {
+        return [
+            ['12345.912', 'en'],
+            ['1.234,5', 'de_DE'],
+        ];
+    }
+
     /**
      * @expectedException \Symfony\Component\Form\Exception\TransformationFailedException
      */
diff --git a/src/Symfony/Component/Form/Tests/Extension/Core/Type/IntegerTypeTest.php b/src/Symfony/Component/Form/Tests/Extension/Core/Type/IntegerTypeTest.php
index 5a9d195f272f..c5c7dd9161b7 100644
--- a/src/Symfony/Component/Form/Tests/Extension/Core/Type/IntegerTypeTest.php
+++ b/src/Symfony/Component/Form/Tests/Extension/Core/Type/IntegerTypeTest.php
@@ -24,14 +24,15 @@ protected function setUp()
         parent::setUp();
     }
 
-    public function testSubmitCastsToInteger()
+    public function testSubmitRejectsFloats()
     {
         $form = $this->factory->create(static::TESTED_TYPE);
 
         $form->submit('1.678');
 
-        $this->assertSame(1, $form->getData());
-        $this->assertSame('1', $form->getViewData());
+        $this->assertTrue($form->isSubmitted());
+        $this->assertFalse($form->isValid());
+        $this->assertFalse($form->isSynchronized());
     }
 
     public function testSubmitNull($expected = null, $norm = null, $view = null)