German patriot here. That is not true. There are no regulation for supermarkets in place other than wearing a mask (which is already retarded...). You do not need a negative test and this goes for the whole country. I really love this movement but we need to be carefull not to believe anything we want to believe. WE do not even have vaxx mandates at work (not that I do not think they will try to implement that soon), so yeah.

edit: no difference is made for vaxxed or unvaxxed. Everybody has to wear a mask here. Reason is that employers and regular folk are by law not allowed to inquire about your vaxx status. So there cannot be someone in front of a supermarket checking that, because that is against the german constitution.