I can't change the currency to € for the Drupal Commerce module I can't change the currency to €.

In admin/commerce/config/currency I set the currency to €. (see capture 1)

But the products still show the $ simbol.(see capture 2)

Is this a bug? 

As StryKaizer commented I need to change it as well in every product. My problem is that I have many products. Is there any way to do it in the database through a query?
I've experienced this bug myself in an older version of Commerce.
Updating to the latest stable version of Commerce fixed the issue.

Also make sure to change the currency on your product(s) too, as changing the global currency won't change it on any already defined products.