Hi Thierry,
I think the issue related to the Gantry5 layout (Home/Default) settings :). Did you set the Home layout to default for all pages instead the Default layout ?
By default, the hydrogen or helium doesn’t assign the page content for Home layout, its assign the page content for the Default layout to present the joomla/wordpress/grav content for all pages (http://docs.gantry.org/gantry5/particles/page-content). Home is a special layout for home page using custom page (http://docs.gantry.org/gantry5/configure/menu-item).
Thank you
