The Czech waiter was admitted to hospital in a very serious condition. He is currently in the Intensive Care Unit after undergoing brain surgery.
His attackers could face up to ten years in jail for grievous bodily harm and public violence.
On their website, the police have published photos of all the perpetrators as well as video of the assault, which took place at a small square near the Quadrio shopping centre.
The waiter told the suspects that they were not permitted to consume alcohol they had brought along with them into the garden.
The group of seven Middle Eastern men then attacked restaurant personnel and knocked one waiter down, where they beat him up and repeatedly kicked him.
They left their victim unconscious, lying on the ground and fled from the scene on Tram number 14 in the direction of the Charles Square, a police spokesman said.
Based on their investigation so far, the investigators believe that the suspects are foreigners, who may be staying in a hotel, hostel or some other type of accommodation in Prague or in the region.
“This is why we are primarily asking hotel service staff and all other witnesses if they saw these men, or if they know where they are staying, to call Emergency Line 158,” said the spokesman.
Police reported the attack on Twitter, said Jan Daněk, spokesman for Prague Police.
Police posted photos of all seven suspects captured on CCTV on the Web, as well as a video of the assault that took place in the square.
Update: On April 23, the perpetrators were caught at the Václav Havel Airport in Prague thanks to visual information supplied by the police. Apparently they “were surprised by the act” of getting caught. It appears that the foreigners had visited Prague before.