Trying to redirect from a language that is no longer in use to another that is not the default

We have decided to remove one of the languages we were using in Guide (fr fr) and redirect to ca fr. I put some custom code loosely based on option 2 in this article https://support.zendesk.com/hc/en-us/articles/4408886627866-Redirecting-traffic-from-deleted-help-center-articles but it automatically reroutes back to the english version of the articles, which is our default language. Is there a way to get around this as I want the transition to be as seamless as possible when going from one version of french to the other. Here is the code I am using: 

if (window.location.href.indexOf("/fr-fr/") > -1) {
    var newURL = window.location.href.replace("/fr-fr/", "/fr-ca/");
    window.location.href = newURL;
}