diff --git a/src/Composer/Command/CreateProjectCommand.php b/src/Composer/Command/CreateProjectCommand.php
index 935370bfc..4a3d33831 100644
--- a/src/Composer/Command/CreateProjectCommand.php
+++ b/src/Composer/Command/CreateProjectCommand.php
@@ -234,8 +234,14 @@ EOT
     {
         if (null === $repositoryUrl) {
             $sourceRepo = new CompositeRepository(Factory::createDefaultRepositories($io, $config));
-        } elseif ("json" === pathinfo($repositoryUrl, PATHINFO_EXTENSION)) {
-            $sourceRepo = new FilesystemRepository(new JsonFile($repositoryUrl, new RemoteFilesystem($io, $config)));
+        } elseif ("json" === pathinfo($repositoryUrl, PATHINFO_EXTENSION) && file_exists($repositoryUrl)) {
+            $json = new JsonFile($repositoryUrl, new RemoteFilesystem($io, $config));
+            $data = $json->read();
+            if (!empty($data['packages']) || !empty($data['includes']) || !empty($data['provider-includes'])) {
+                $sourceRepo = new ComposerRepository(array('url' => 'file://' . strtr(realpath($repositoryUrl), '\\', '/')), $io, $config);
+            } else {
+                $sourceRepo = new FilesystemRepository($json);
+            }
         } elseif (0 === strpos($repositoryUrl, 'http')) {
             $sourceRepo = new ComposerRepository(array('url' => $repositoryUrl), $io, $config);
         } else {
diff --git a/src/Composer/Repository/ComposerRepository.php b/src/Composer/Repository/ComposerRepository.php
index 459fa55a7..d5d8c11ef 100644
--- a/src/Composer/Repository/ComposerRepository.php
+++ b/src/Composer/Repository/ComposerRepository.php
@@ -85,7 +85,7 @@ class ComposerRepository extends ArrayRepository
         $this->config = $config;
         $this->options = $repoConfig['options'];
         $this->url = $repoConfig['url'];
-        $this->baseUrl = rtrim(preg_replace('{^(.*)(?:/packages.json)?(?:[?#].*)?$}', '$1', $this->url), '/');
+        $this->baseUrl = rtrim(preg_replace('{^(.*)(?:/[^/\\]+.json)?(?:[?#].*)?$}', '$1', $this->url), '/');
         $this->io = $io;
         $this->cache = new Cache($io, $config->get('cache-repo-dir').'/'.preg_replace('{[^a-z0-9.]}i', '-', $this->url), 'a-z0-9.$');
         $this->loader = new ArrayLoader();
@@ -395,7 +395,7 @@ class ComposerRepository extends ArrayRepository
 
         $jsonUrlParts = parse_url($this->url);
 
-        if (isset($jsonUrlParts['path']) && false !== strpos($jsonUrlParts['path'], '/packages.json')) {
+        if (isset($jsonUrlParts['path']) && false !== strpos($jsonUrlParts['path'], '.json')) {
             $jsonUrl = $this->url;
         } else {
             $jsonUrl = $this->url . '/packages.json';