diff --git a/src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php b/src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php
index 4089aee5a1..5d46be0b32 100644
--- a/src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php
+++ b/src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php
@@ -136,6 +136,7 @@ class Configuration implements ConfigurationInterface
                 ->scalarNode('optimizations')->end()
                 ->arrayNode('paths')
                     ->normalizeKeys(false)
+                    ->useAttributeAsKey('paths')
                     ->beforeNormalization()
                         ->always()
                         ->then(function ($paths) {