Special characters from ISO-8859-1 encode website come out mangled (�) in Google search results

Google is getting confused because while the page is ISO-8859-1, some content is loaded into the page in UTF-8. This causes Googlebot to have to re-encode the content page content as UTF-8 so that it can process it. Something is going wrong during that process and characters are getting mangled.

For example, you use a JavaScript library for consenting to cookies. It loads UTF-8 encoded text and writes it into the page.

Ideally Google would be able to deal with this situation without getting the characters garbled. I contacted Google about this and a bug has been filed on their end. However, some other sites that are getting re-encoded are working. Whatever is happening with your site isn't affecting a lot of other sites, so it may be a lower priority fix for Google.

As a workaround you could ensure that your page and JavaScript all use the same character set. Since you don't have control over third party libraries that use UTF-8 and can't convert them to ISO-8859-1, you would have to convert your site to UTF-8.

In general, there is no good reason to use ISO-8859-1 these days. That character set only support 256 characters. UTF-8 doesn't make the page size significantly larger and it supports all unicode characters:

• The extra French characters Œ, œ, and Ÿ
• The Euro sign (€), ellipses (…), non-breaking space ( )
• Fun characters like arrows and emoji

Using UTF-8 allows you support user generated content from any language. At the very least, it allows users names to be written correctly, no matter their national origin.

So far i see, french diacritical signs are not a part of ISO-8859-1 (beside of apostrophe). The cache version of Google doesn't contain these characters.

I see two workarounds:

1. Encode the whole content as UTF-8 (would be the way i prefer)
2. Encode diacritical signs as HTML entities. Example: séries becomes séries. This can be done in an editor like Notepad++ and HTML Tag plugin. This is a bunch of manual work - i wouldn't do it.

BTW. you have a page https://www.hypnoweb.net/www/, which mirrors the startpage - not good.