error messages

I use validates_presence_of in my model and I use the yml file to have
the error message translate into:

Veuillez vérifier les champs suivants :

    * Material doit être rempli(e)

But how can I translate the name of the attribute that is blank? I
want to translate Material also into French.

http://guides.rubyonrails.org/i18n.html#translations-for-active-record-models

Fred