The robbery was reported at about 7:20 p.m. Monday in the 800 block of Market Street between Fourth and Fifth streets.
The suspect came into the business, pointed a handgun at an employee, grabbed the shades from a display case and fled, according to police.
The suspect, a man in his mid-20s, had not been found as of this morning.
No one was injured in the robbery.
Anyone with information about the case is encouraged to call the Police Department's anonymous tip line at (415) 575-4444 or send a tip by text message to TIP411.