Symfony2 repository standard folder or namespace

I am creating a Repository to use it with an Entity in a Symfony2 project, but I do not know where to store the class. I have been researching in Internet but I do not have any info about the default namespace o default folder to store the Repositories.

I could "think" in two approaches:

1. use Entity folder: (entity and entityRepository in the same folder)

   /project/bundle/entity;

2. use Repository folder: (entity in entity folder and repository in Repository one)

   /project/bundle/entity; /project/entity/repository;

There are any standard about that?