The documentary crew was shooting at the Dashashwamedh Ghat in the temple town without any permission, officials said.
The crew team comprised four arrested Indians besides four foreigners - two from the US and two Australians - who have been detained.
Of the Indians, two hail from Haryana and one each from Mumbai and Delhi.
Police officers told IANS the crew was shooting the "Ganga aarti" with a drone camera and also a heli-camera but they did not have permission for this.
The crew had taken permission for the shoot between July 5 and 7. They were asked not to extend the shoot without official nod from the district administration.
The four have been booked under various sections of the Indian Penal Code at the Dashashwamedh Ghat police station.
Security has been upped at various ghats in the temple town after the Sheetla Ghat blasts in 2010.
The Intelligence Bureau had of late alerted the state police of potential terror threat to Varanasi, after which security was further heightened.
Varanasi has attained VVIP status after Prime Minister Narendra Modi was elected to the Lok Sabha from here.