Zend Framework + Doctrine - Duplicated insertions

I've integrated Zend Framework 1.11.9 with Doctrine 2.1 following this tutorial : http://www.michaelgallego.fr/blog/?p=45 (it's in french btw)

It's working well except that when I persist an object, it's inserting the s开发者_如何学运维ame object twice.

Any idea?