According to what is done by [_form_field partial](https://github.com/real-chocopanda/sfTwitterBootstrapPlugin/blob/master/data/generator/sfPropelModule/twitter/template/templates/_form_field.php#L6)

we should put %error% directly in ````<div class=\"controls\">````

````
<div class=\"control-group\">\n  %label%\n  <div class=\"controls\">%error% %field%%help%\n%hidden_fields%</div>\n</div>
`````

I don't know which one is better but if would be nice to standardize the generated markup, no ?