"Eine Manufaktur" is a factory manufacturing a product, but not the modern mass production type. It's rather old-fashioned relying on true craftsmanship creating artisan products of unique and exquisit quality. Often the word "manufacture" is used, but I would try to use words like 'craft', 'craftsmanship', or 'artisan' in the description of this kind of factory. So if you had a sentence like "Dieses Porzellangeschirr wurde in einer traditionellen 800 Jahre alten Manufaktur hergestellt.", this could be "This china was fashioned by craftsmen in a traditional 800 year old artisan workshop." in English.
