Add to ckeditor/config.js
CKEDITOR.editorConfig = function(config) {
config.contentsCss = [
'/assets/myCkeditorStyles.css', // any other file to encapsulate custom styles
'/assets/myFontFaceTags.css'
];
}
It's not enough to provide the font face tags within your public folder. You have to explixitly call it within the ckeditor/config.js
.
You also might be interested in CKEditor asset pipline support.