If you are gaijin the police ask for a license. I knew a guy from Peru who sold jewelry on his time off and he was taken into the police station several times. He was let go (minus his jewelry) but always packed up when he saw police after that.
Another strange thing was I had a Chinese girlfriend (she was a Japanese citizen though) who had a school. One of the Japanese students got angry at a teacher and reported to the police that my girlfriend allowed students to sell used costumes to each other (my girlfriend didn't know about it). A policeman called my girlfriend and told her she needed a permit to sell used items. She agreed to come and get one but was told that there was a test involved and since she was a foreigner (she is fluent in Japanese) she had to send an employee (Japanese) instead. She did and got the permit. Strange thinking.
