According to a police report, the perpetrators threatened employees with a handgun and then made off with the loot in the direction of Färberplatz.
Police have launched a manhunt. The trio carried out the robbery at around 9:40am. One of them was wearing a light brown cap and a scarf, while a second suspect was dressed in dark clothes and carried a black bag. A third suspect acted as a look-out.
There were no injuries in the robbery. The value of the stolen items has not yet been disclosed.
Austria has been a regular target for jewel heists from a gang known as the Pink Panthers.
The group is behind armed robberies targeting high-end jewellery stores in Europe, the Middle East, Asia and the United States.
They are believed to have carried out robberies worth in excess of €330 million since 1999. Hundreds of suspects are linked to more than 340 robberies in 35 countries.
Many gang members are known to originate from the former Yugoslavia, but they work across countries and continents.
On Tuesday, four Israelis suspected of having links to the Pink Panthers were arrested at a hotel in Vienna for attempting to fence €500 million worth of stolen goods taken in earlier robberies.