Moving wordpress site from HTTP to HTTPS ERR_TOO_MANY_REDIRECTS

First you must Update the Site Address under Settings > General. Make sure the address is https://www.followourtrack.fr/. After that update your .htaccess like below.

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
</IfModule>

That .htaccess can work with fine in my server.