The Tiananmen Square Massacre was a response to a protest in the People's Republic of China (PRC) in 1989. Also known as the June Fourth Incident, it occurred when several waves of protests across the course of a few months came to a head. The PRC government debated over whether to try to defuse the situation through discussion, but eventually decided to suppress it militarily. Estimates of how many students were killed range from hundreds to thousands. This led to mass criticisms and sanctions around the world, and has remained a controversial topic into the 21st century.
We must not forget that the government who did this is still in power, and is the same government our country has a free trade deal with.