You pay taxes according to the laws of the country you live in. I do not have any idea what German Law is, but it's likely that if Google and Amazon are required to send the equivalent of a 1099 here in the USA they will know you earned income and you will likely be required to pay tax on that income. If it's a paltry sum it probably wouldn't matter much. In the United States a 1099 is required by any company that pays you $600 or more. When I outsource USA labor I send 1099's, if I outsource outside of the USA I do not.