The Spanish government revealed on Saturday that 75 people have been arrested, 51 in Spain and 24 in France, including the two Barcelona-based suspected heads of the organisation in Europe.
Investigators released video showing police officers searching a house at an undisclosed location in Barcelona.
False identification documents and production equipment were said to have been uncovered during the operation.
The gang allegedly charged up to 50,000 euros to transport Chinese nationals to the US, Britain, Spain, France, Greece, Italy and Turkey.
Some of the people trafficked ended up in the sex trade, the ministry said.
The gang’s main European hub was Barcelona airport. It allegedly used the northeastern city as a stopping-off point for Chinese nationals while false documents were prepared.
Today hundreds of A21 supporters gathered at London’s parliament for #27for27, an awareness initiativeâ?¦ http://t.co/TklZ4XbNT2
The news of the arrests comes as the A21 campaign, whose goal is to abolish slavery in the 21st century, staged a demonstration in central London to highlight awareness of people trafficking.