True compulsory education is free of tuition. You can check the compulsory education system in other countries at will.

The Hong Kong Public Schools and Vocational Training Council has implemented 12 free education since September 2008, and public primary schools have implemented small class teaching in stages since the first class in the 2009- 10 school year.

However, compulsory education in Hong Kong is only exempt from tuition and miscellaneous fees. You still have to pay for books yourself.