What country do you live in? Australia
Is beer as a product in general (commercial/non commercial) taxed in your country? Yes
Are you allowed to produce homebrew beer, that is tax free? Yes
Is there some amount limitation of homebrew beer that you are allowed to produce without paying taxes? When homebrewing was legalised in the 1970s, it was 20L per week, but that law is now defunct, and no limit is stated.
Is there any legal obligation considering for instance an obligation to fill a report or announcement as a homebrewer and send it to your legal authorities in order to be allowed to brew beer at home? No, thank heavens.