I found where data should be put now ! I tried the method from @Bugatti but it doesn’t work now. I also try to copy them here : Internal Storage / Android / data / com.whatsapp /. It’s not working.
But the solution is quite the same, you have to put your backup (following the initial method of this thread) here : Internal Storage / Android / media / com.whatsapp / WhatsApp /. And you copy there all your folders from your previous phone : Backups, Databases and Media.
After that, you will have a message after lauching whatsapp for the first time saying you can restaure old data. If you don’t have this message, you just copy data in the wrong place.