Yesterday was the 55th anniversary of the first official raising of the Papuan Morning Star flag when the indigenous people of the former Dutch New Guinea declared independence.
The Morning Star was subsequently banned after Indonesia took over, but an increasing number of global rallies mark this anniversary in support of Papuans.
This year, non-Papuan Indonesians were among the hundreds who demonstrated in the capital and were blasted by water cannons, before police arrested 203 of them.
A public interest lawyer who was present, Veronica Koman, said demonstrators were roughed up by undercover police, and that ten of those taken in by police sustained injuries.
Ms Koman said police didn't cite any particular alleged breach of the law in making the arrests.
She said it follows an ongoing pattern of infringement of constitutional rights.
"It's just basic freedom of expression. As long as Papua is still a part of Indonesia it means they still have the right to freedom of expression, and it's being violated systematically by the state."
Veronica Koman, said 14 demonstrators were also arrested in the Indonesian city of Yogyakarta
Photo: AFP (Water cannons are used against protesters in Jakarta)