Pathauto doesn't work anymore when i change the default language I've got a big problem this morning.

I'm working with english as default language Administration » Configuration » Regional and language. It's much more easy to me to work with the interface in english.

But this morning i have to change the default language to french because my boss want the interface in French (and the website is almost finished)

But unfortunately, all my alias doesn't work anymore like before www.example.com/my-article is becoming www.example/node/5.
More precisely, it's only alias from content type who doesn't work fine because taxonomy term are ok.

Does someone has a idea why when i changed the default language in Administration » Configuration » Regional and language (english to french) my alias didn't worked anymore?
This happens because the table url_alias has a language property that doesn't match anymore with the default language. Try to change the language code to your default language or delete the information. (Of course, make a backup before in case of).