I am a Belgian living and working on China how can I apply for a visa to Mongolia?

Garance, there are mixed but rare information on the internet about how to get Mongolian entry permit for foreigners in China. Therefore, I think the best way would be to contact the embassy directly and find out the right answer. Here is the contact information:

Chancery and Residence: No. 2, Xiu Shui Bei Jie, Jian Guo Men Wai, Chaoyang District, Beijing
Tel: 010-65326512 Ext. 108
Fax: 010-65326216
Email: beijingmfat.gov.mn