Hey Patrick,

You have to install Joomla French language from your backend > Extension > language manager > find `French` language > click Install

Second, access your backend again > Easyblog > language > (if there got require insert your API key, you have go to http://stackideas.com/dashboard copy your API key and paste in required field) > click Run > click discover button > select French language > click install/update

Hope this help.