I need a visa to China to participate in competitions. How fast can I get a single entry one?

Daniil, if you stay less than 90 days, then you should apply for a M type from Chinese embassy in Luxembourg. It requires your passport, finished application form affixed with a recent six months passport photo, invitation letter from the competition host, round trip air tickets and hotel booking. If you burden all the expense during your stay, you should provide financial proof, bank statement or income certificate. By the way, your valid resident permit (original and copy versions) should be submitted.

It usually takes four days to deal with your application. The fee is around 35 Euros.