Police arrested a protester with “Occupy SF” in front of the Federal Reserve Bank of San Francisco this morning.

Witnesses said two officers approached a man sitting at the corner of Spear and Market streets after smelling marijuana smoke. The man extinguished the marijuana before being asked for his medical marijuana card, they said.

A protester who identified himself as “Gypsy” said police confiscated the man’s cannabis card and threatened him with arrest.

Gypsy, who told a couple of people to record the incident on video, said he approached the group and tried to explain medical marijuana laws, acting as an on-the-spot legal counsel, but was told to go away by police.

“I was told I was interfering with a police investigation and told to go away,” Gypsy said. “Police were asking that legal counsel be denied.”

Gypsy said the man jokingly tried to run away and stopped before the two officers tackled and arrested him.

A Federal Reserve police officer said the man was arrested for assault.