I am currently halfway with my degree program in germany and as part of the requirement of finish the course I will
have to complete a 6 month internship, I would like to do my internship in Singapore or Japan but I dont know where to start,
Ive tried e-mailing several companies but got not much response.
You should try checking with your university regarding internship programmes. Most universities have some sort of link-ups with companies or whatnot on providing students with internships that are relevant to their course of study.
If you're just randomly emailing companies asking for internship opportunities, I wouldn't expect a lot of response, to be honest. But it is different if you are doing this as part of the university's agreement with the company in question.
I've met a few Germans who are here on internships. Perhaps you could try contacting the German embassy in Singapore for some links. Good luck!