WordPress Translation to french, at -> à not working

No matter what languages your site are in, when using WPML you should never install a localised WordPress version, instead you should just install the default one (i.e. US English).

Also make sure that you didn’t change the LANG definition in your wp-config.php file, so that should read: define ('WPLANG', '');

Then you need to make sure that all the strings are in English (go to WPML->String Translation, scroll down to the bottom where you can set the language of the strings). After that rescan your theme for strings and you will be able to add translations for “at” in both German and French.