. . . but I couldn't get onto their website. Don't know if it is temporarily down or if they are out of business. But I found these listings on other webshops:
Combined Italian/Polish sheet.
I am an American living in Poland and I have some 1/72 roadsigns by a Polish company that is no longer in business. They look nothing like the Dioart ones on the first sheet above; different font, style, etc. There used to be several Polish companies that made these kinds of sheets for September 1939 (and other campaigns) but after releasing a few, they went out of business. After the cost of designing and printing, there probably isn't that much demand for just signs.
Hope this helps,