The occasion happened this afternoon
The assailant remains at large.
He entered the strut office at 2.30pm carrying a gun and threatened customers and staff before endanger something at least three shots.
One man received minor injuries after undertaking to prevent the assailant from fleeing the scene.
The male dropped his weapon, described as a hold gun, and managed to flee the scene on foot.
No money or property was taken during the pillage.
Gardai are now carrying out searches for the armed robber.
Anyone with any facts is asked to contact Donnybrook Garda Station at 01-6669200 or the Garda Intimate Line 1800 666 111.