When you've got many language or region variations that you simply mark up with hreflang, then Each and every of such versions ought to have a canonical tag pointing to by itself. Including this code to every page of your internet site is probably inconvenient and impractical, but most material https://addons.prestashop.com/de/seo-suchmaschinenranking-optimization/31857-automatische-google-rich-snippets-json-ld-opengraph-seo.html